2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1007
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
P0030 and P0036
The ECM detects an open in the heater circuits of the HO2S when the heater is commanded OFF. The condition exists for greater than 4 s or a
cumulative of 30 s.
P0031 and P0037
The ECM detects a short to ground in the heater circuits of the HO2S when the heater is commanded OFF. The condition exists for greater than 4 s
or a cumulative of 30 s.
P0032 and P0038
The ECM detects a short to voltage in the heater circuits of the HO2S when the heater is commanded ON. The condition exists for greater than 4 s
or a cumulative of 30 s.
Action Taken When the DTC Sets
DTCs P0030, P0031, P0032, P0036, P0037, and P0038 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0030, P0031, P0032, P0036, P0037, and P0038 are Type B DTCs.
Diagnostic Aids
* If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool circuit
status parameters for the component. The circuit status parameters change from OK or Not Run to Fault if there is a condition with the circuit
or a connection.
* An open fuse in the HO2S heater circuit may be caused by the heater element in one of the sensors. The condition may not be present until
the sensor operates for a period of time. If no fault is present in the heater circuit, monitor the amperage of each heater using the DMM to
determine if one of the heater elements is the cause of the open fuse. Inspect the sensor pigtail or the harness for contacting the exhaust
