P3400 OBD II Trouble Code Cylinder Deactivation System Bank 1

How to easily diagnose, repair, and info on causes of a P3400 trouble code that indicates cylinder deactivation of system bank 1.

Symptoms of P3400 OBD II Trouble Code

  • Diminished fuel efficiency
  • Reduced engine performance
  • Other cylinder deactivation codes
  • Engine misfire codes

Common Causes of P3400 OBD II Trouble Code

  • Low engine oil level or pressure
  • Defective valve timing control solenoid/s
  • Open or shorted cylinder deactivation circuit/s
  • Faulty PCM or PCM programming error

Severity of P3400 OBD II Trouble Code

Aside from the fact that cylinder deactivation problems may diminish fuel efficiency, the possible causes may lead to catastrophic engine failure. The P3400 should be rectified as soon as possible and classified as severe.