P04A1 OBD II Trouble Code Exhaust Pressure Control Valve B Low
How to quickly diagnose, repair, and info on symptoms and causes of a P04A1 trouble code which is an abnormal low condition with the B exhaust pressure control valve.
Symptoms of P04A1 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 P04A1 OBD II Trouble Code
- Short to Power in the power supply circuit between the exhaust pressure control solenoid and the PCM (powertrain control module)
- Open in the power supply circuit between the exhaust pressure control solenoid and the PCM
- Short to ground in the power supply circuit to the exhaust pressure control solenoid
- Exhaust Pressure Control Relay faulty
- Exhaust Pressure Control Solenoid faulty
- Possibly the PCM has failed (highly unlikely)