2010 Cadillac CTS Sedan AWD V6-3.6L Page 911
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 Bank 1 Sensor 1
DTC P0031
- HO2S Heater Control Circuit Low Voltage Bank 1 Sensor 1
DTC P0032
- HO2S Heater Control Circuit High Voltage Bank 1 Sensor 1
DTC P0036
- Heater Control Circuit Bank 1 Sensor 2
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:
