Possible Causes
| Possible Causes |
|---|
| (K243) O2 2/2 SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE |
| (K904) O2 RETURN (DOWNSTREAM) CIRCUIT FOR A SHORT TO VOLTAGE |
| (K243) O2 2/2 SIGNAL CIRCUIT FOR A SHORT TO THE (K399) O2 2/2 HEATER CONTROL CIRCUIT |
| (K243) O2 2/2 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE |
| (K904) O2 RETURN (DOWNSTREAM) CIRCUIT OPEN OR HIGH RESISTANCE |
| 2/2 OXYGEN SENSOR |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .