2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 3002
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Showing posts with label * The system voltage is between 9-16 volts.. Show all posts
Showing posts with label * The system voltage is between 9-16 volts.. Show all posts
Tuesday, December 22, 2020
Saturday, December 19, 2020
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2945
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2945
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Thursday, December 17, 2020
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2888
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2888
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Wednesday, December 16, 2020
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2857
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2857
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur from this specific module.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
The modules is never signaled, therefore the specific subsystems will not function.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* When testing circuits to the SDGM access can be accomplished by removing the instrument panel center trim panel. Note that this procedure
does not allow removal of the SDGM, only access to the connector. Refer to Instrument Panel Center Trim Panel Replacement (Cadillac) (
See: Body and Frame/Interior Moulding / Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel
Replacement (Cadillac))Instrument Panel Center Trim Panel Replacement (Except Cadillac) (See: Body and Frame/Interior Moulding /
Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel Replacement (Except Cadillac)).
* DTC U1816 can set current in the HPCM, ECM, and the SDGM.
* If DTC U1816 is only set in the HPCM, the PIM must be replaced due to all circuits between the HPCM and MCM being internal to the PIM.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Verification
1. Verify that DTC B137A is not current in the serial data gateway module (SDGM).
瀚慖f the DTC is current in the SDGM, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Verify that DTC U1816 is not set current only in the HPCM.
瀚慖f the DTC is current in the HPCM only, replace the drive motor power inverter module (PIM).
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X1 at the PIM.
2. Test for less than 5 ohms between the PIM case and ground.
瀚慖f greater than the specified range, test the ground strap for an open/high resistance. If the circuit tests normal, replace the PIM.
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur from this specific module.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
The modules is never signaled, therefore the specific subsystems will not function.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* When testing circuits to the SDGM access can be accomplished by removing the instrument panel center trim panel. Note that this procedure
does not allow removal of the SDGM, only access to the connector. Refer to Instrument Panel Center Trim Panel Replacement (Cadillac) (
See: Body and Frame/Interior Moulding / Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel
Replacement (Cadillac))Instrument Panel Center Trim Panel Replacement (Except Cadillac) (See: Body and Frame/Interior Moulding /
Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel Replacement (Except Cadillac)).
* DTC U1816 can set current in the HPCM, ECM, and the SDGM.
* If DTC U1816 is only set in the HPCM, the PIM must be replaced due to all circuits between the HPCM and MCM being internal to the PIM.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Verification
1. Verify that DTC B137A is not current in the serial data gateway module (SDGM).
瀚慖f the DTC is current in the SDGM, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Verify that DTC U1816 is not set current only in the HPCM.
瀚慖f the DTC is current in the HPCM only, replace the drive motor power inverter module (PIM).
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X1 at the PIM.
2. Test for less than 5 ohms between the PIM case and ground.
瀚慖f greater than the specified range, test the ground strap for an open/high resistance. If the circuit tests normal, replace the PIM.
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2853
2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2853
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
The BCM senses a short to ground on the accessory wake up serial data circuit.
Action Taken When the DTC Sets
* The modules use a default value for the missing parameters until the next ignition cycle.
* The module(s) is never signaled, therefore the specific subsystem(s) will not function.
* The vehicle may not start.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
Short to ground may also set multiple no communication codes for GMLAN high speed modules.
Reference Information
Schematic Reference
* DLIS Fuse and Ignition Switch in Power Distribution Schematics (See: Diagrams/Electrical Diagrams/Starting and Charging/Power and
Ground Distribution/System Diagram/Power Distribution Schematics)
* Body Control System Schematics (See: Body and Frame/Body Control Systems/Diagrams/Electrical Diagrams)
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Testing
1. With the ignition OFF, disconnect the module harness connectors listed below one at a time. After each disconnect, retest for current DTCs.
DTC U1814 should remain current.
* Engine control module (ECM) - X1
* Transmission control module (TCM) - X1
* Transfer case control module (TCCM) (RPO NP8) - X2
* Serial data gateway module (SDGM) (RPO HP2) - X2
瀚慖f the DTC becomes history, replace the module disconnected before the DTC became history.
2. Ignition OFF, disconnect the X4 harness connector at the BCM.
3. Test for infinite resistance between the accessory wake up serial data circuit terminal 19 and ground.
瀚慖f less than the specified range, test the serial data circuit for a short to ground.
4. If the circuit tests normal, replace the BCM.
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
The BCM senses a short to ground on the accessory wake up serial data circuit.
Action Taken When the DTC Sets
* The modules use a default value for the missing parameters until the next ignition cycle.
* The module(s) is never signaled, therefore the specific subsystem(s) will not function.
* The vehicle may not start.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
Short to ground may also set multiple no communication codes for GMLAN high speed modules.
Reference Information
Schematic Reference
* DLIS Fuse and Ignition Switch in Power Distribution Schematics (See: Diagrams/Electrical Diagrams/Starting and Charging/Power and
Ground Distribution/System Diagram/Power Distribution Schematics)
* Body Control System Schematics (See: Body and Frame/Body Control Systems/Diagrams/Electrical Diagrams)
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Testing
1. With the ignition OFF, disconnect the module harness connectors listed below one at a time. After each disconnect, retest for current DTCs.
DTC U1814 should remain current.
* Engine control module (ECM) - X1
* Transmission control module (TCM) - X1
* Transfer case control module (TCCM) (RPO NP8) - X2
* Serial data gateway module (SDGM) (RPO HP2) - X2
瀚慖f the DTC becomes history, replace the module disconnected before the DTC became history.
2. Ignition OFF, disconnect the X4 harness connector at the BCM.
3. Test for infinite resistance between the accessory wake up serial data circuit terminal 19 and ground.
瀚慖f less than the specified range, test the serial data circuit for a short to ground.
4. If the circuit tests normal, replace the BCM.
Monday, August 10, 2020
2010 Cadillac Truck Escalade RWD V8-6.2L Page 3002
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* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Saturday, August 8, 2020
2010 Cadillac Truck Escalade RWD V8-6.2L Page 2945
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* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Thursday, August 6, 2020
2010 Cadillac Truck Escalade RWD V8-6.2L Page 2888
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* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.
* System OFF lamps will illuminate for these systems.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no
associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are
transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically
after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:
- A control module on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more modules was interrupted during diagnosis.
- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.
- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.
These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system
inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.
* Use to determine if the module uses high or low speed GMLAN serial data communications.
* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and
the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control
module.
* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,
providing the vehicle is equipped with the control module.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Hybrid
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW
* Antilock Brake System Schematics (See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Diagrams/Electrical
Diagrams) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
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2010 Cadillac Truck Escalade RWD V8-6.2L Page 2857
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* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur from this specific module.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
The modules is never signaled, therefore the specific subsystems will not function.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* When testing circuits to the SDGM access can be accomplished by removing the instrument panel center trim panel. Note that this procedure
does not allow removal of the SDGM, only access to the connector. Refer to Instrument Panel Center Trim Panel Replacement (Cadillac) (
See: Body and Frame/Interior Moulding / Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel
Replacement (Cadillac))Instrument Panel Center Trim Panel Replacement (Except Cadillac) (See: Body and Frame/Interior Moulding /
Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel Replacement (Except Cadillac)).
* DTC U1816 can set current in the HPCM, ECM, and the SDGM.
* If DTC U1816 is only set in the HPCM, the PIM must be replaced due to all circuits between the HPCM and MCM being internal to the PIM.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Verification
1. Verify that DTC B137A is not current in the serial data gateway module (SDGM).
瀚慖f the DTC is current in the SDGM, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Verify that DTC U1816 is not set current only in the HPCM.
瀚慖f the DTC is current in the HPCM only, replace the drive motor power inverter module (PIM).
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X1 at the PIM.
2. Test for less than 5 ohms between the PIM case and ground.
瀚慖f greater than the specified range, test the ground strap for an open/high resistance. If the circuit tests normal, replace the PIM.
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur from this specific module.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter module availability has not been received.
Action Taken When the DTC Sets
The modules is never signaled, therefore the specific subsystems will not function.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
* When testing circuits to the SDGM access can be accomplished by removing the instrument panel center trim panel. Note that this procedure
does not allow removal of the SDGM, only access to the connector. Refer to Instrument Panel Center Trim Panel Replacement (Cadillac) (
See: Body and Frame/Interior Moulding / Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel
Replacement (Cadillac))Instrument Panel Center Trim Panel Replacement (Except Cadillac) (See: Body and Frame/Interior Moulding /
Trim/Dashboard / Instrument Panel/Service and Repair/Instrument Panel Center Trim Panel Replacement (Except Cadillac)).
* DTC U1816 can set current in the HPCM, ECM, and the SDGM.
* If DTC U1816 is only set in the HPCM, the PIM must be replaced due to all circuits between the HPCM and MCM being internal to the PIM.
Reference Information
Schematic Reference
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Verification
1. Verify that DTC B137A is not current in the serial data gateway module (SDGM).
瀚慖f the DTC is current in the SDGM, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Verify that DTC U1816 is not set current only in the HPCM.
瀚慖f the DTC is current in the HPCM only, replace the drive motor power inverter module (PIM).
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X1 at the PIM.
2. Test for less than 5 ohms between the PIM case and ground.
瀚慖f greater than the specified range, test the ground strap for an open/high resistance. If the circuit tests normal, replace the PIM.
2010 Cadillac Truck Escalade RWD V8-6.2L Page 2853
2010 Cadillac Truck Escalade RWD V8-6.2L Page 2853
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
The BCM senses a short to ground on the accessory wake up serial data circuit.
Action Taken When the DTC Sets
* The modules use a default value for the missing parameters until the next ignition cycle.
* The module(s) is never signaled, therefore the specific subsystem(s) will not function.
* The vehicle may not start.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
Short to ground may also set multiple no communication codes for GMLAN high speed modules.
Reference Information
Schematic Reference
* DLIS Fuse and Ignition Switch in Power Distribution Schematics (See: Diagrams/Electrical Diagrams/Starting and Charging/Power and
Ground Distribution/System Diagram/Power Distribution Schematics)
* Body Control System Schematics (See: Body and Frame/Body Control Systems/Diagrams/Electrical Diagrams)
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Testing
1. With the ignition OFF, disconnect the module harness connectors listed below one at a time. After each disconnect, retest for current DTCs.
DTC U1814 should remain current.
* Engine control module (ECM) - X1
* Transmission control module (TCM) - X1
* Transfer case control module (TCCM) (RPO NP8) - X2
* Serial data gateway module (SDGM) (RPO HP2) - X2
瀚慖f the DTC becomes history, replace the module disconnected before the DTC became history.
2. Ignition OFF, disconnect the X4 harness connector at the BCM.
3. Test for infinite resistance between the accessory wake up serial data circuit terminal 19 and ground.
瀚慖f less than the specified range, test the serial data circuit for a short to ground.
4. If the circuit tests normal, replace the BCM.
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
The BCM senses a short to ground on the accessory wake up serial data circuit.
Action Taken When the DTC Sets
* The modules use a default value for the missing parameters until the next ignition cycle.
* The module(s) is never signaled, therefore the specific subsystem(s) will not function.
* The vehicle may not start.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Diagnostic Aids
Short to ground may also set multiple no communication codes for GMLAN high speed modules.
Reference Information
Schematic Reference
* DLIS Fuse and Ignition Switch in Power Distribution Schematics (See: Diagrams/Electrical Diagrams/Starting and Charging/Power and
Ground Distribution/System Diagram/Power Distribution Schematics)
* Body Control System Schematics (See: Body and Frame/Body Control Systems/Diagrams/Electrical Diagrams)
* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical
Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Testing
1. With the ignition OFF, disconnect the module harness connectors listed below one at a time. After each disconnect, retest for current DTCs.
DTC U1814 should remain current.
* Engine control module (ECM) - X1
* Transmission control module (TCM) - X1
* Transfer case control module (TCCM) (RPO NP8) - X2
* Serial data gateway module (SDGM) (RPO HP2) - X2
瀚慖f the DTC becomes history, replace the module disconnected before the DTC became history.
2. Ignition OFF, disconnect the X4 harness connector at the BCM.
3. Test for infinite resistance between the accessory wake up serial data circuit terminal 19 and ground.
瀚慖f less than the specified range, test the serial data circuit for a short to ground.
4. If the circuit tests normal, replace the BCM.
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