P0139 Ford

Ford P0139 OBD-II Trouble Code Definition:

P0139 HO2S Circuit Slow Response Bank 1 Sensor 2

P0139 Ford OBD-II Trouble CodeDescription:

OBD Trouble Code P0139
O2 Sensor Circuit Slow Response
What does the code mean? OBD-ii Code P0139 definition:
This involves the rear oxygen sensor on the driver’s side. This code indicates the engine air fuel ratio is not being adjusted by the oxygen sensor signal or the ECM as expected to do so, or not adjusted as often as expected to do so once the engine is warmed or under normal engine use.
Symptoms Sumptoms of OBD code P0139
You will likely not notice any drivability problems, although there may be symptoms.
Causes Causes of the OBD-II code P0139
A code P0139 may mean that one or more of the following has happened: The oxygen sensor is faulty The wiring to the sensor is broken / frayed There is an exhaust leak
Solutions The simplest thing to do is to reset the code and see if it comes back. If the code comes back, the problem is more than likely the rear driver’s side oxygen sensor. You will likely wind up replacing it but you should also consider these Solutions: Check and fix any exhaust leaks Check for wiring problems (shorted, frayed wires) Check the frequency and amplitude of the oxygen sensor (advanced) Check for a deteriorating / contaminated oxygen sensor, replace if necessary Check for inlet air leaks Check the MAF sensor for proper operation