P0139 OBD II Trouble Code Oxygen Sensor Circuit Slow Response (Bank1, Sensor2)

Symptoms of P0139 OBD II Trouble Code

  • The oxygen sensor is faulty
  • The wiring to the sensor is broken / frayed
  • There is an exhaust leak

Common Causes of P0139 OBD II Trouble Code

  • 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