2010 Cadillac CTS Sedan AWD V6-3.6L Page 1086
- HO2S Heater Performance Bank 2 Sensor 1
DTC P0161
- HO2S Heater Performance 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 sensor's 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
P0135 or P0155
* Before the ECM can report DTC P0135 or P0155 failed, P0030, P0031, P0032, P0050, P0051, and P0052 must run and pass.
* DTC P0130, P0131, P0132, P0134, P0150, P0151, P0152, or P0154 is not set.
* The engine speed is greater than 240 RPM.
* The ignition voltage is 10-18 volts.
* The intake air temperature (IAT) is greater than -30掳C (-22掳F).
* After the previous ignition cycle the engine OFF time was greater than 2 minutes, 0 seconds for LLT.
* The calculated exhaust temperature is between 300-750掳C (572-1,382掳F).
* The calculated exhaust temperature is colder than 750掳C (1,382掳F), for LLT.
* The engine is not in decel fuel cut-off (DFCO).
* The HO2S 1 is at operating temperature for greater than 10 seconds.
* The internal HO2S 1 resistance is less than 10,000 ohms.
* The HO2S 1 heater is enabled for greater than 120 seconds.
* DTCs P0135 and P0155 run continuously once the above conditions are met for approximately 100 seconds.
P0141 or P0161
* Before the ECM can report DTC P0141 or P0161 failed, DTCs P0036, P0037, P0038, P0056, P0057, and P0058 must run and pass.
* DTCs P0137, P0138, P0140, P0157, P0158, or P0160 are not set.
* The engine speed is greater than 240 RPM.
* The ignition voltage is 10-18 volts.
* The intake air temperature (IAT) is greater than -30掳C (-22掳F).
* After the previous ignition cycle the engine OFF time was greater than 0 seconds.
* The calculated exhaust temperature is 300-750掳C (572-1,382掳F), 300-700掳C (572-1,292掳F) for LLT.
* The engine is not in decel fuel cut-off (DFCO).
* The internal HO2S 2 resistance is less than 10,000 ohms.
* The HO2S 2 heater is enabled for greater than 120 seconds.
* DTCs P0141 and P0161 run continuously once the above conditions are met for approximately 100 seconds.
Conditions for Setting the DTC
P0135 or P0155
The ECM detects that the internal resistance of the HO2S 1 heater is not within the expected range for greater than 12 seconds.
P0141 or P0161
The ECM detects that the internal resistance of the HO2S 2 heater is not within the expected range for greater than 6 seconds.
