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Powertrain fault code

P0312: Cylinder 12 Misfire Detected

Stop and check

If the engine light is flashing, stop driving: unburnt fuel can destroy the catalytic converter.

What P0312 means

One cylinder is not firing properly.

Common causes

  • Worn spark plug on that cylinder
  • Failed ignition coil
  • Faulty or blocked injector
  • Low compression on that cylinder

What to check first

  1. Swap the coil with a neighbouring cylinder and see whether the misfire moves.
  2. Check the spark plug on that cylinder.
  3. Have a compression test done if plug and coil are fine.

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Read your car's codes yourself, free

Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.

Open the free scan tool

Need help with P0312?

Tell us your car and what it is doing with P0312. We reply by email with what to check first, in plain words. Free.

Related codes

P0301P0302P0303P0304P0305P0306P0307P0308

General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.