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.
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the scan tool and wait 60 seconds to ensure all modules are powered down.
- Ignition OFF, disconnect the harness connector at the HO2S 2.
- Ignition OFF, measure for less than 5 ohms between the HO2S 2 low signal circuit terminal A and ground.
- If more than the specified range, test the HO2S 2 low signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, verify the scan tool HO2S 2 parameter is approximately 450 mV.
- If more than the specified value, test the HO2S 2 high signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- If less than the specified value, test the HO2S 2 high signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
- Ignition ON, install a 3 A fused jumper wire at the HO2S 2 high signal circuit terminal B. Toggle the other end of the jumper wire between the HO2S 2 low signal circuit terminal A and battery voltage. Verify the scan tool HO2S 2 parameter toggles between 0 mV and approximately 1,000 mV.
- If the scan tool HO2S 2 parameter does not toggle correctly, test the HO2S 2 high signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
- If all circuits test normal, replace the HO2S 2.
NOTE:
All modules must be powered down or misdiagnosis may result.