2010 Cadillac CTS Sedan AWD V6-3.6L Page 937

2010 Cadillac CTS Sedan AWD V6-3.6L Page 937

DTC P0037

- HO2S Heater Control Circuit Low Voltage Bank 1 Sensor 2

DTC P0038

- HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2

DTC P0050

- HO2S Heater Control Circuit Bank 2 Sensor 1

DTC P0051

- HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1

DTC P0052

- HO2S Heater Control Circuit High Voltage Bank 2 Sensor 1

DTC P0056

- HO2S Heater Control Circuit Bank 2 Sensor 2

DTC P0057

- HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 2

DTC P0058

- HO2S Heater Control Circuit High Voltage Bank 2 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.

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.