Diagnostic Test
- CHECK FOR AN ACTIVE DTC
- With the scan tool, read DTCs.
Is the DTC active?
Yes
- Go To 2
No
- Test complete.
- With the scan tool, read DTCs.
- CHECK CONNECTIONS FOR POWERTRAIN CONTROL MODULE AND DOWNSTREAM O2 SENSOR
- Check for the presence of loose electrical connections at the Powertrain Control Module and the Downstream O2 Sensor.
Were any loose electrical connections present?
Yes
- Restore the correct connections.
No
- Go To 3
- Check for the presence of loose electrical connections at the Powertrain Control Module and the Downstream O2 Sensor.
- WIRING INSULATION CHECK
- Check the correct insulation of the wiring between the Downstream O2 Sensor and Powertrain Control Module.
Were any faults with the Downstream O2 Sensor wiring insulation found?
Yes
- Restore the correct insulation for the wiring.
No
- Go To 4
- Check the correct insulation of the wiring between the Downstream O2 Sensor and Powertrain Control Module.
- DOWNSTREAM O2 SENSOR
- Check that the Upstream Oxygen Sensor is working properly.
Is the Downstream Oxygen Sensor working properly?
Yes
- End of diagnosis.
No
- Replace the Downstream Oxygen Sensor. Refer to SENSOR, OXYGEN, REMOVAL AND INSTALLATION .
- Check that the Upstream Oxygen Sensor is working properly.