2010 Cadillac CTS Sedan AWD V6-3.6L Page 945
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
* Heated Oxygen Sensor Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Heated
Oxygen Sensor Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine idling, command the appropriate B52 HO2S heater ON and OFF with a scan tool while observing the B52 HO2S Heater Circuit Test
Status parameter. The parameter should display OK or Not Run.
2. Engine idling at operating temperature, observe the scan tool B52 HO2S Heater parameter. The amperage should be within 0.2-1.5 A.
3. Engine idling at operating temperature, move the related wiring and connectors while observing the B52 HO2S Heater parameter with a scan
tool. The parameter should not change with movement.
瀚慖f movement affects the parameter, repair the appropriate harness or connector.
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the
conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate B52 HO2S.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground.
瀚慖f the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests
normal and the B52 HO2S heater circuit fuse is open, test all components connected to the fuse and replace as necessary.
3. Ignition ON, observe the appropriate scan tool HO2S Heater Control Open Circuit Test Status parameter. The parameter should display
Malfunction.
瀚慖f not the specified value, test the heater control circuit terminal E for a short to ground, or for a short to voltage. If the circuit tests
normal, replace the K20 ECM.
4. Connect a 3 A fused jumper wire between the heater control circuit terminal E and ground. Observe the appropriate scan tool HO2S Heater
Control Circuit Low Voltage Test Status parameter. The parameter should transition from OK to Malfunction.
瀚慖f not the specified value, test the heater control circuit terminal E for an open/high resistance. If the circuit tests normal, replace the K20
ECM.
Note:
* Less than 10 ohm of additional resistance on the ignition voltage circuit, or control circuit may set a DTC. If there is resistance on a
circuit, the driver will remain ON and the scan tool HO2S High Voltage Test Status parameter will display OK.
* Performing this test may set additional DTCs.
5. Ignition OFF, connect a 10 A fused jumper wire between the control circuit terminal E and the ignition voltage circuit terminal D.
6. Engine idling, observe the appropriate HO2S Control Circuit High Voltage Test Status parameter. The parameter should transition from Not
Run to Malfunction.
瀚慖f not the specified value, test the control circuit and the ignition voltage circuit for high resistance. If the circuits test normal, replace the
K20 ECM.
7. If all circuits test normal, test or replace the appropriate B52 HO2S.
Repair Instructions
Caution: Refer to Heated Oxygen Sensor Resistance Learn Reset Caution (See: Powertrain Management/Computers and Control
Systems/Oxygen Sensor/Service Precautions/Heated Oxygen Sensor Resistance Learn Reset Caution).
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen
