Engine Light On

What is an ECU?

Check Engine indicators

Different types of Check Engine indicators

Modern cars have a high number and vast array of Electronic Control Units (ECU’s).

The engine has an Engine Electronic Control Unit (or Engine Computer), which is designed to control every aspect of the engines running, from ignition timing, fuel injection, emissions and so on.

Your engine has a wide variety of sensors and actuators that provide inputs and outputs to the Engine Electronic Control Unit (or Engine Computer). The engine computer is constantly monitoring and adjusting levels to keep the air / fuel mixture at around 14.7 to 1, which is the ideal air fuel ratio for most engines in modern cars.

So why is my Check Engine light flashing?

If any sensor or actuator goes out of range by approximately 1.5 times its designed tolerance, then the self diagnostic routines in the cars engine computer store a fault code, or trouble code. This will generally always bring a warning light on the dash most commonly called the Check Engine Light (CEL) or Malfunction Indicator Light (MIL Light).

The Check Engine Light (CEL) or Malfunction Indicator Light (MIL Light) are designed to warn the driver that there is a fault with the vehicle that needs attention.

Therefore if you have a Check Engine Light (CEL) or Malfunction Indicator Light (MIL Light) light glowing on your dash or coming on intermittently while driving it is very important that you get the fault codes and live data read as soon as possible to avoid possible future, more costly damage.

Diagnosing your engine fault

Grimmer Motors uses a range of the best, state of the art scan tools that will read the fault codes and live data from your vehicle. Our skilled, trained and qualified technicians combined with our leading edge analysis technology mean that we will quickly and easily read the fault codes and live data from your vehicle, provide you with a diagnostic printout, and repair the faults as required. Call us now to book in your “scan” to read your engine codes.

Please Note: Electronic Tests depend on the vehicle technology and may not be possible on some vehicles.

Conveniently located in Fairfield, Grimmer Motors have been providing quality service to Hamilton since the company was established in 1934. When you receive battery-related services through Grimmer Motors, you can trust our fully qualified mechanics to safely and efficiently service your vehicle, advising you before further repair work is conducted.


Live/work in any of the following areas? Grimmer Motors could be extra convenient for you.Fairfield

  • Fairview Downs
  • Enderly
  • Claudelands
  • Peachgrove
  • Hamilton East
  • Chartwell
  • Chedworth
  • Central Hamilton
  • Forest Lake, Beerescourt
  • Frankton
  • Melville
  • Waikato



Grimmer Motors Ltd


Paul Johns

Booked the ol' Fuga in for a service this week. I dropped it off early to take advantage of the free clean and asked if I could have it ready at 3 pm. The service went well and they... pointed out things that would need attention in the future. I like the introduction of the vehicle service and repair log book. Which has all my previous services and fix ups recorded in it. And the Fuga was freshly cleaned and ready at 3pm, like they said. Thanks Team

Cinn Thornton

The team at Grimmer Motors are very friendly and have awesome customer service. My car needed scan as flashing light on dash. The problem was identified , easy to ... understand explanation given and quote for fix provided. Thanks team.

Pip Six

Awesome service. They communicated really well with me about what was going on and then fixed a few extras on the same day I took my van in. A great place.

Lincoln Fernandes

Fast easy reliable and much cheaper compared to dealerships

Hamish O'neill

Great customer service, good communication and works done on time. Thanks Grimmers

Sarah Bowers

Love leaving our car(s) in the friendly and capable hands at Grimmer Motors. Everything from drop off, reception, communication and the work done is of a high standard... and much apprecaited. Another happy customer - thanks Grimmers.