Possible Causes
| POSSIBLE CAUSES |
|---|
| O2 1/1 SIGNAL CIRCUIT SHORTED TO VOLTAGE |
| O2 1/1 RETURN CIRCUIT SHORTED TO VOLTAGE |
| O2 1/1 SIGNAL CIRCUIT SHORTED TO THE O2 1/1 HEATER CONTROL CIRCUIT |
| O2 1/1 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE |
| O2 1/1 RETURN CIRCUIT OPEN OR HIGH RESISTANCE |
| OXYGEN SENSOR 1/1 |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .