P0138

Test 1 - 4:

Test 5 - 8:

Test 9:

SYMPTOM
P0138-O2 SENSOR 1/2 CIRCUIT VOLTAGE TOO HIGH

TEST NOTE
This symptom is diagnosed using the test P0132-O2 SENSOR 1/1 CIRCUIT VOLTAGE TOO HIGH.

WHEN MONITORED
With battery voltage greater than 10.4 volts, engine running for more than 4 minutes and coolant temperature above 180 °F.

SET CONDITION
The oxygen sensor voltage is above 1.5 volts.

POSSIBLE CAUSES
- O2 sensor above 1.5 volts
- O2 sensor operation
- O2 sensor signal shorted to voltage
- O2 sensor signal circuit open
- O2 sensor signal circuit shorted to O2 heater supply circuit
- (K4) sensor ground circuit open
- O2 sensor heater control circuit open
- O2 sensor heater ground control circuit open
- PCM