2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 990
Note: The ignition circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components
for being shorted that share the ignition circuit.
瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and
the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
3. Connect a test lamp between the heater control circuit terminal 2 and B+. The test lamp should not illuminate.
瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit/connections test normal, replace the K20 Engine
Control Module.
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.
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 Engine Control Module.
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
Engine Control Module.
6. If all circuits/connections test normal, test or replace the B52 Heated Oxygen Sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the B52 Heated Oxygen Sensor.
2. Test for 5-25 ohm between the control terminal 2 and the ignition terminal 1 of the B52 Heated Oxygen Sensor.
瀚慖f not within the specified range, replace the B52 Heated Oxygen 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
P0031
DTC P0030, P0031, P0032, P0036, P0037, or P0038 (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 P0030
- HO2S Heater Control Circuit Sensor 1
DTC P0031
- HO2S Heater Control Circuit Low Voltage Sensor 1
DTC P0032
- HO2S Heater Control Circuit High Voltage Sensor 1
