Possible Causes
| Possible Causes |
|---|
| O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO GROUND |
| O2 RETURN CIRCUIT SHORTED TO GROUND |
| O2 SENSOR 1/1 |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .