P0139

Test 1 - 3:

Test 4 - 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 60 MPH. Throttle open for a minimum 120 seconds. Coolant Temp greater than 70° C (158° F). RPM between 1200 to 2000. Vacuum between 56Kpa to 28Kpa.

SET CONDITION
The O2 sensor voltage does not switch properly from lean to rich during monitoring. Two Trip Fault.

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