P0139 2002 HYUNDAI ELANTRA HO2S Circuit Slow Response Bank 1 Sensor 2
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