Symptoms of P0391 OBD II Trouble Code
- Malfunction Indicator Lamp (MIL) illumination (a.k.a. check engine light)
- Lack of power
- Possible no start condition
Common Causes of P0391 OBD II Trouble Code
- Faulty camshaft position sensor (CMP) "B"
- Poor wiring connection at cam sensor "B"
- Electrical short or open condition in associated wiring
- Low/bad battery