2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 988
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 P0030
- HO2S Heater Control Circuit Sensor 1
DTC P0031
- HO2S Heater Control Circuit Low Voltage Sensor 1
DTC P0032
- HO2S Heater Control Circuit High Voltage Sensor 1
DTC P0036
- Heater Control Circuit Sensor 2
DTC P0037
- HO2S Heater Control Circuit Low Voltage Sensor 2
DTC P0038
- HO2S Heater Control Circuit High Voltage Sensor 2
Diagnostic Fault Information
Circuit Description
The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the
operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the
sensor heater. The Engine Control Module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors
are cold. This prevents the possibility of thermal shock to the sensor, from condensation build-up on the sensor, by controlling the sensors rate of
heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature,
the ECM may modulate the heater control circuit to ground, to maintain a desired temperature.
The ECM controls the heater by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback
circuit that is pulled-up to voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring
the feedback voltage.
Conditions for Running the DTC
P0030, P0031, P0032
* The ignition voltage is between 10-18 V.
* The engine speed is greater than 80 RPM.
* The HO2S heater is commanded ON and OFF at least once during the ignition cycle.
* The DTCs run continuously once the above conditions are met for 1 second.
P0036, P0037, P0038
* The ignition voltage is between 10-18 V.
* The engine speed is greater than 80 RPM.
* The HO2S heater is commanded ON and OFF at least once during the ignition cycle.
* The HO2S 2 is at operating temperature.
* The DTCs run continuously once the above conditions are met for 1 second.
Conditions for Setting the DTC
