Circuit/System Testing
WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the harness connector at the HO2S 2.
- Ignition ON, verify that a test lamp illuminates between the HO2S 2 heater voltage supply circuit terminal D and ground.
- If the test lamp does not illuminate, test the HO2S 2 heater voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all components connected to the fuse and replace as necessary.
- Ignition ON, verify that a test lamp does not illuminate between the HO2S 2 heater low control circuit terminal C and the HO2S 2 heater voltage supply circuit terminal D.
- If the test lamp illuminates, test the HO2S 2 heater low control circuit for a short to ground. If the circuit tests normal, replace the ECM.
- Engine running, leave the test lamp connected from the previous step. The lamp should flash or be ON steady.
- If the test lamp is not ON steady or flashing, test the HO2S 2 heater low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
- If the ECM and all circuits test normal, replace the HO2S 2.