2010 Cadillac CTS Sedan AWD V6-3.6L Page 918
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.
The HO2S utilizes the following circuits:
* A signal circuit
* A low reference circuit
* An ignition voltage circuit
* A heater control circuit
Conditions for Running the DTC
P0030, P0031, P0032, P0050, P0051, P0052
* The ignition voltage is between 10-18 volts.
* The engine speed is greater than 80 RPM, 240 RPM for LLT.
* The HO2S heater is commanded ON and OFF at least once during the ignition cycle.
* The HO2S heater is commanded ON-LLT only.
* The DTCs run continuously when the above conditions are met-5 seconds for LLT.
P0036, P0037, P0038, P0056, P0057, P0058
* The ignition voltage is between 10-18 volts.
* 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 when the above conditions are met for greater than 500 mS.
Conditions for Setting the DTC
P0030, P0036, P0050, and P0056
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 seconds or
a cumulative of 30 seconds.
P0031, P0037, P0051, and P0057
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
seconds or a cumulative of 30 seconds.
P0032, P0038, P0052, and P0058
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
seconds or a cumulative of 30 seconds.
Action Taken When the DTC Sets
DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, and P0058 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, and P0058 are Type B DTCs.
