Possible Causes
| Possible Causes |
|---|
| (K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO GROUND |
| (K243) O2 2/2 SIGNAL CIRCUIT SHORTED TO GROUND |
| (K243) O2 SIGNAL CIRCUIT SHORTED TO THE (K904) O2 RETURN DOWNSTREAM CIRCUIT |
| (K243) O2 SIGNAL CIRCUIT SHORTED TO THE (Z42) O2 2/2 HEATER GROUND CIRCUIT |
| O2 SENSOR |
| PCM |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding.