Possible Causes
| Possible Causes |
|---|
| (K399) O2 2/2 HEATER CONTROL CIRCUIT OPEN |
| (Z42) O2 2/2 HEATER GROUND CIRCUIT OPEN |
| (K399) O2 2/2 HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE |
| 2/2 O2 SENSOR |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding.