P0138

Tests 1 - 3:

Tests 4 - 6:

SYMPTOM
P0138 - 1/2 O2 SENSOR SHORTED TO VOLTAGE

WHEN MONITORED
With the ignition key ON.

SET CONDITION
The engine running for more than 2 minutes and engine coolant temperature above 176 °F. The oxygen sensor signal voltage is above 1.2 volts for 30 seconds.

POSSIBLE CAUSES
- 1/2 O2 sensor signal circuit shorted to voltage
- 1/2 O2 sensor connector and harness intermittent defect
- 1/2 O2 sensor connector and harness observable defect
- 1/2 O2 sensor defective
- PCM connector observable defect