Symptoms of P0679 OBD II Trouble Code
- The engine management computer (PCM) will set the code P0679
- The engine will be hard to start or may not start at all in cold weather or when its been sitting long enough for the block to cool.
- Lack of power until the engine heats up sufficiently.
- Engine may miss due to the colder than normal cylinder head temperature
- Engine may hesitate when accelerating
- No pre-heat period, or in other words the preheat light does not go off.
Common Causes of P0679 OBD II Trouble Code
- Faulty cylinder #9 glow plug
- Open or shorted glow plug circuit
- Damaged wiring connector
- Faulty glow plug control module