2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1105
瀚慖f test lamp illuminates, test the heater control circuit for a short to ground. If the circuit/connections test normal, replace the K20 ECM.
4. Idle the engine, and verify the test lamp illuminates or flashes.
瀚慖f the test lamp is always OFF, test the control circuit terminal 2 for an open/high resistance. If the circuit/connections test normal, replace
the K20 ECM.
Note: The control circuit for the HO2S heater is pulled-up to voltage within the ECM, 2.0-3.0 V on the control circuit is normal.
5. Ignition ON, test for 2.0-3.0 V between the control circuit terminal 2 and ground.
瀚慖f not within the specified range, test the control circuit for a short to voltage. If the circuit/connections test normal, replace the K20
ECM.
6. If all circuits/connections test normal, test or replace the B52 HO2S.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate B52 heated oxygen sensor (HO2S) sensor.
2. Test for 5-25 ohm between the control terminal 2 and the ignition terminal 1 of the B52 heated oxygen sensor (HO2S) sensor.
瀚慖f not within the specified range, replace the B52 HO2S sensor.
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)
* Heated Oxygen Sensor Replacement - Sensor 2 (LAU) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair/Heated Oxygen Sensor Replacement - Sensor 2)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and
programming
P0137
DTC P0137, P0138, or P0140 (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 P0137
- HO2S Circuit Low Voltage Sensor 2
DTC P0138
- HO2S Circuit High Voltage Sensor 2
DTC P0140
- HO2S Circuit Insufficient Activity Sensor 2
Diagnostic Fault Information
Typical Scan Tool Data
