Ignition Coil Failure
Ignition Coil Failure
Section titled “Ignition Coil Failure”The M54 uses individual coil-on-plug ignition coils for each cylinder. They fail with age and heat exposure.
Symptoms
Section titled “Symptoms”- Misfire (rough running, flashing check engine light)
- Fault codes: P0301-P0306 (individual cylinder misfire)
- Reduced power
- Rough idle
- Poor fuel economy
Diagnosis
Section titled “Diagnosis”- Read fault codes to identify affected cylinder(s)
- Swap suspected coil to different cylinder
- If misfire follows the coil, it’s confirmed faulty
- Check spark plug condition when removing coils
Replacement
Section titled “Replacement”See DIY: Spark Plug Replacement guide — coils are removed in the same process.
Recommendations
Section titled “Recommendations”- Replace all 6 coils at the same time (they’re the same age)
- Bosch or Delphi recommended
- Replace spark plugs when replacing coils
- Inspect coil boots for cracks or carbon tracking