P0139

Test 1-5:

SYMPTOM
P0139-O2 SENSOR 1/2 SLOW RESPONSE

TEST NOTE
This symptom is diagnosed using the test P0133-O2 SENSOR 1/1 SLOW RESPONSE.

WHEN MONITORED
Start and drive vehicle greater than 20 MPH and less than 55 MPH. Throttle open for a minimum 120 seconds. Coolant Temp greater than 70 degrees C (158 degrees F) Catalytic Converter Temperature greater than 600 degrees C (1112 degrees F)

SET CONDITION
The PCM monitors the state of change of the front O2 sensor and the rear 02 sensor. The PCM will then compare the differences between both readings, if the differences are greater than a calibrated amount the PCM will record a fault. Two trip failure.

POSSIBLE CAUSES
- Good trip equal to zero
- Exhaust leak
- O2 signal circuit
- O2 return circuit
- O2 sensor