Possible Causes
| POSSIBLE CAUSES |
|---|
| O2 SENSOR 1/1 RETURN CIRCUIT SHORT TO BATTERY VOLTAGE |
| O2 SENSOR 1/1 SIGNAL CIRCUIT SHORT TO BATTERY VOLTAGE |
| O2 SENSOR 1/1 |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .