Circuit/System Verification

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON.
Verify no HO2S heater DTCs are set.
- If a DTC is set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Go to next step: If a DTC is not set
Verify none of the conditions listed below exist:
- Lean or rich fuel injectors - Refer to Fuel Injector Diagnosis .
- Water intrusion in the HO2S harness connector
- Low or high fuel system pressure - Refer to Fuel System Diagnosis .
- Fuel that is contaminated - Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Fuel saturation of the evaporative emission (EVAP) canister
- Exhaust leaks
- Engine vacuum leaks
- Engine oil consumption - Refer to Oil Consumption Diagnosis .
- Engine coolant consumption - Refer to Loss of Coolant .
- If any of the above conditions exist
  Repair as necessary.
- Go to next step: If none of the conditions exist
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.
Verify the DTC does not reset.
- If the DTC sets
  Test or replace the appropriate B52 HO2S.
- Go to next step: If the DTC does not set
All OK.