Possible Causes
| Possible Causes |
|---|
| O2 SENSOR 1/1 RETURN CIRCUIT SHORTED TO GROUND |
| O2 SENSOR 1/2 RETURN CIRCUIT SHORTED TO GROUND |
| O2 SENSOR 1/1 RETURN CIRCUIT OPEN |
| O2 SENSOR 1/2 RETURN CIRCUIT OPEN |
| EXHAUST LEAK |
| ENGINE MECHANICAL CONDITION |
| AGING O2 SENSOR |
| CATALYTIC CONVERTER |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .