2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 154
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B048D 01
- Auxiliary Heater Temperature Command Circuit Short to Battery
DTC B048D 06
- Auxiliary Heater Temperature Command Circuit Low Voltage/Open
DTC B048E 00
- Auxiliary Heater System Malfunction
Circuit/System Description
The HVAC control module sends a pulse width modulation (PWM) signal to the electrical auxiliary heater, if the interior temperature is too low
and additional heat is requested. The request signal from the HVAC control module, battery positive, ignition and ground circuits enable the
electrical auxiliary heater to operate. Through the signal circuit the electrical auxiliary heater sends via a PWM signal the current status to the
HVAC control module.
Conditions for Running the DTC
* Ignition ON.
* The HVAC control module is ON.
* The electrical auxiliary heater is ON.
Conditions for Setting the DTC
B048D 01
The voltage at the HVAC control module output to the electrical auxiliary heater is always high.
B048D 06
The voltage at the HVAC control module output to the electrical auxiliary heater is always low or floating.
B048E 00
The feedback signal of the electrical auxiliary heater does not correspond with the requested PWM signal.
Action Taken When the DTC Sets
The electrical auxiliary heater is inoperative.
Conditions for Clearing the DTC
The feedback signal of the electrical auxiliary heater corresponds with the requested PWM signal.
Reference Information
Schematic Reference
HVAC Schematics (See: Heating and Air Conditioning/Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
Description and Operation
Automatic HVAC Description and Operation (See: Heating and Air Conditioning/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)
