2010 Cadillac CTS Sedan AWD V6-3.6L Page 1100
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine idling, observe the appropriate scan tool HO2S voltage parameter. The voltage should fluctuate above and below the range of
350-550 mV.
2. 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 HO2S.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.
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. Ignition OFF, connect a test lamp between the heater control circuit terminal D and B+.
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 for an open/high resistance. If the circuit/connections test normal, replace the ECM.
5. Ignition ON, verify that the appropriate scan tool HO2S voltage parameter is between 350-500 mV.
瀚慖f less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the
ECM.
瀚慖f greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace
the ECM.
6. Connect a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage parameter is less than
60 mV.
瀚慖f greater than the specified range, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the
ECM.
7. Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool HO2S
voltage parameter is less than 60 mV.
瀚慖f greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the
circuit/connections test normal, replace the ECM.
8. Verify that none of the following conditions exist:
* The HO2S is loose
* Lean or rich condition.
* Water intrusion in the HO2S harness connector
* Low or high fuel system pressure-Refer to Fuel System Diagnosis (See: Powertrain Management/Computers and Control
Systems/Testing and Inspection/Component Tests and General Diagnostics/Fuel System Diagnosis).
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) (See: Powertrain
Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool))Alcohol/Contaminants-in-Fuel Diagnosis (without Special
Tool) (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)).
* Fuel saturation of the evaporative emission (EVAP) canister
* Exhaust leaks near the HO2S
* Engine vacuum leaks
瀚慖f you find any of the above conditions, repair as necessary.
9. If all circuits/connections test normal, replace the appropriate HO2S.
Repair Instructions
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
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
