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.
- CHECK THE DOWNSTREAM O2 SENSOR WIRING CONTINUITY
- Check the correct continuity of the wiring between the Downstream O2 Sensor and the Powertrain Control Module.
Does the wiring have continuity?
Yes
- Go To 4
No
- Restore the correct continuity for the wiring.
- Check the correct continuity of the wiring between the Downstream O2 Sensor and the Powertrain Control Module.
- CHECK OPERATION OF THE DOWNSTREAM
- Swap the Upstream and Downstream O2 Sensors.
- Check that the Downstream O2 Sensor is working properly.
Is the Downstream O2 Sensor working properly. Did the fault follow the component?
Yes
- Replace the Downstream O2 Sensor. Refer to SENSOR, OXYGEN, REMOVAL AND INSTALLATION .
No
- Go To 5
- CHECK OPERATION OF THE DOWNSTREAM O2 SENSOR
- Verify that the Downstream O2 Sensor is working correctly.
Is the Downstream O2 Sensor working correctly?
Yes
- End of diagnosis.
No
- Replace the Downstream O2 Sensor. Refer to SENSOR, OXYGEN, REMOVAL AND INSTALLATION .
- Verify that the Downstream O2 Sensor is working correctly.