Diagnostic Procedures
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Run engine above 1500 RPM for 2 minutes. Ensure ECT is more than 158°F (70°C). Let engine idle. Using scan tool, monitor HO2S bank 2 sensor 1. If reading is varying outside 400-538 mV, ensure no corrosion is present in the HO2S bank 2 sensor 1 harness connector and that all terminals (heater and signal) are contacting correctly. If connector is okay, replace HO2S bank 2 sensor 1. If reading is not varying outside 400-538 mV, see DTC P0154: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 2, SENSOR 1 for circuit diagnosis.