Possible Causes
| Possible Causes |
|---|
| EXHAUST SYSTEM LEAK |
| ENGINE MECHANICAL/LOW CYLINDER COMPRESSION |
| UPSTREAM O2 SENSOR WIRING ISSUE |
| UPSTREAM O2 SENSOR |
| DOWNSTREAM O2 SENSOR WIRING ISSUE |
| DOWNSTREAM O2 SENSOR |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .