P0139 INFINITI HO2S12 Slow Response

Possible causes
– Faulty Rear Heated Oxygen Sensor Bank 1
– Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
– Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks
Tech description
Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.
When is the obd code mean?
The P0139 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor takes more time to respond between rich and lean than the specified time.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– High Fuel Consumption
– Excessive Smoke from Exhaust
P0139 INFINITI OBD Code Description