2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1103

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1103

瀚慖f you find any of the above conditions, repair as necessary.

9. If all circuits/connections test normal, replace the B52 HO2S 1.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Heated Oxygen Sensor Replacement - Sensor 1 (LAU) (See: Powertrain Management/Computers and Control Systems/Oxygen

Sensor/Service and Repair/Heated Oxygen Sensor Replacement - Sensor 1)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and

programming

P0135

DTC P0135 or P0141 (Without LF1)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

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 P0135

- HO2S Heater Performance Sensor 1

DTC P0141

- HO2S Heater Performance 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

* Before the ECM can report DTC P0135 failed, P0030, P0031, and P0032 must run and pass.

* DTC P0130, P0131, P0132, or P0134 is not set.

* The engine is operating.

* 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.

* The calculated exhaust temperature is less than 524掳C (975掳F).

* 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 ohm.

* DTCs P0135 runs continuously once the above conditions are met for approximately 100 seconds.