P04A0 OBD II Trouble Code Exhaust Pressure Control Valve B Range Performance

How to quickly diagnose, repair, and info on symptoms and causes of a P04A2 trouble code which is a range or performance problem with the B exhaust pressure control valve.

Symptoms of P04A0 OBD II Trouble Code

  • Malfunction Indicator Lamp (MIL) illuminated
  • Lack of power
  • Lack of engine braking
  • Longer than normal cold engine warmup time

Common Causes of P04A0 OBD II Trouble Code

  • Stuck Exhaust Back Pressure Valve
  • Possibly stuck / damaged / misadjusted turbocharger wastegate
  • Exhaust system restriction / leaks
  • Exhaust Gas Pressure Sensor
  • Possibly the PCM has failed (highly unlikely)