What is the ignition control module?New Car ICM Hamilton NZ

Your car’s ignition module is responsible for switching off and on 12 volts to your ignition coils from energy supplied from your cars battery and electrical charging system.  It is also responsible for the switching action to your ignition coils therefore creating sparks in your engine, which ignite the air/fuel mixture which powers the engine. The ignition control module (or ICM) manages and regulates the generation of sparks through the ignition coils, allowing an optimum amount of spark ignition to take place within the engine. This results in your car to starting properly and continuing to run smoothly.

In most cars, the ignition control module is located in the distributor housing near the ignition coil. If it fails or ceases to work correctly, the ignition process can be affected. This can result in a variety of issues ranging from small misfires to your car not starting at all. Fortunately, an ignition control module (ICM) replacement will take care of the problem.

Learn more about how the ignition works >


Causes of a faulty ignition control module:

  • Faulty wiring – Short-circuiting, damaged wiring and loose connections to the spark plugs can all affect the ignition control module’s ability to receive and distribute electricity. This can result in it not functioning at all.
  • Open circuit spark plug – if secondary side of the ignition coil (spark plug side) is open circuited for any reason, then the collapsing magnetic field and resulting very high voltage in the ignition coil has to find a path to earth somehow. This can lead to high voltage spike damage to the ignition control module.
  • Overheating – The ignition coil is usually coated with a heat-resistant material which protects the electrical components. However, it can still be prone to overheating, especially if it is old or worn. An overheating ignition control module will wear at a much higher rate and fail quickly.


Symptoms of ignition control module issues:

  • Misfiring – A misfire occurs when fuel isn’t burnt correctly, usually because your engine missed a process in its combustion cycle. If your engine’s fuel mixture is unable to ignite properly, this will likely happen when you are driving.
  • Reduced engine performance – If your engine is not sparking correctly, it will lose power. This will lead to decreased acceleration. Fuel will also not be burnt correctly and go to waste, affecting your car’s fuel economy and dramatically increasing harmful green house gas emissions.
  • Engine not starting – If the ignition control module completely fails, there will be no spark in your engine when you turn the keys. This will prevent the car from starting.
  • Car stops randomly – sometimes the ignition control module can fail intermittently, causing your engine to stop / stall while you are driving. Often this can happen when a failing ignition module heats up.


Ignition Control Module (ICM) Replacement Service in Hamilton

Is your car in need of a new ignition control module? If so, we can help! At Grimmer Motors, our team of experienced mechanics can locate, diagnose and replace the ignition control module. This will allow for correct ignition and improved engine performance.

Additionally, we do all sorts of ignition replacements ranging from battery replacement to spark plugs and ignition coils.

For ignition control module replacement and more in Hamilton, contact Grimmer Motors today!

Please Note – we don’t generally stock or supply just “parts only” for this service. We are a general automotive repair workshop. If you are able to bring your vehicle to us, we can diagnose the problem, find and fit the necessary parts, or organise the appropriate service for you.


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