Browse over 9,000 car reviews

What is a car's ECU?

Technology Car Advice
...
Laura Berry
Senior Journalist
25 Jun 2024
2 min read

Q: What is ECU in car?

A: ECU stands for Engine Control Unit. An ECU, which is sometimes referred to as an engine management system (ECM) or the engine control module or even electronic control unit, is an engine computer which ensures a combustion engine runs effectively and efficiently.

Think of an ECU as a combustion engine’s brain. This small computer receives information from sensors and then makes decisions ranging from adjusting the air-fuel mixture in the cylinders to idle speed.

The location of an ECU varies depending on the make and model of the car. (image: Ken Research)
The location of an ECU varies depending on the make and model of the car. (image: Ken Research)

All modern cars with combustion engines have an ECU and they’re vital to the engine functioning properly. While a new consumption engine can’t operate without an ECU it’s possible to drive a car with a faulty ECU. However, the engine is not likely to be given the right instructions to run efficiently or offer optimal performance.

If there is a fault with your vehicle’s ECU an orange 'check engine' icon will illuminate in your instrument cluster. Driving with a faulty ECU is not recommended as further engine damage may occur.

The location of an ECU varies depending on the make and model of the car but they are commonly found in the engine bay, inside the dashboard or under the front passenger seat. The car’s manual should be able to indicate where the ECU is located.

ECU stands for Engine Control Unit. (image: Infinium Global Research)
ECU stands for Engine Control Unit. (image: Infinium Global Research)
Laura Berry
Senior Journalist
Laura Berry is a best-selling Australian author and journalist who has been reviewing cars for almost 20 years.  Much more of a Hot Wheels girl than a Matchbox one, she grew up in a family that would spend every Friday night sitting on a hill at the Speedway watching Sprintcars slide in the mud. The best part of this was being given money to buy stickers. She loved stickers… which then turned into a love of tattoos. Out of boredom, she learnt to drive at 14 on her parents’ bush property in what can only be described as a heavily modified Toyota LandCruiser.   At the age of 17 she was told she couldn’t have a V8 Holden ute by her mother, which led to Laura and her father laying in the driveway for three months building a six-cylinder ute with more horsepower than a V8.   Since then she’s only ever owned V8s, with a Ford Falcon XW and a Holden Monaro CV8 part of her collection over the years.  Laura has authored two books and worked as a journalist writing about science, cars, music, TV, cars, art, food, cars, finance, architecture, theatre, cars, film and cars. But, mainly cars.   A wife and parent, her current daily driver is a chopped 1951 Ford Tudor with a V8.
About Author

Comments