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.

NOTE: If DTC P0036, P0037 or P0038 is also set, diagnose that DTC first. Then, if DTC P0140 is also set, diagnose that DTC next. See DTC P0036: HO2S HEATER CIRCUIT - BANK 1, SENSOR 2 , DTC P0037: HO2S HEATER CIRCUIT - LOW VOLTAGE - BANK 1, SENSOR 2 , DTC P0038: HO2S HEATER CIRCUIT - HIGH VOLTAGE - BANK 1, SENSOR 2 or DTC P0140: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 1, SENSOR 2 .

Run engine above 2500 RPM for 2 minutes. Ensure ECT is more than 176°F (80°C). Let engine idle. Using scan tool, monitor HO2S bank 1 sensor 2. If reading is varying outside 401-519 mV, ensure no corrosion is present in the HO2S bank 1 sensor 2 harness connector and that all terminals (heater and signal) are contacting correctly. If okay, replace HO2S bank 1 sensor 2. If reading is not varying outside 401-519 mV, see DTC P0140: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 1, SENSOR 2 for diagnosis.