Code 13 - Open O2 Sensor Circuit
NOTE:
If Codes 13 and 23 exist, start with Code 23.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This step checks if ECM can respond to lean O2 sensor signal (low voltage).
- This step determines if there is an open O2 sensor wire or faulty ECM.
- This step checks for bad ground to ECM.