car ECU

Your car’s ECU (engine control unit) is a key part of how your vehicle runs, responsible for many of the functions of your car engine. That means if there’s a problem with your engine, it could very much be down to your ECU. Now, if you’re interested in used cars and want to know a little bit more about the ECU, then you’ll be glad to hear that you’ve come to the right place! We’re not just the best place for online car auctions – we’ve also authored this handy guide that’s ideal for anyone looking for a jumping off point in familiarising themselves with their ECU.

What is an ECU?

The ECU is a device that controls different functions within your car. There are numerous ECUs points on the system, with up to 80 in modern vehicles. Each one regulates a certain part of your car, which is why it is often the first port of call for mechanics when their vehicle has engine issues.

Each ECU point controls its particular function but receives input from different relevant areas of the vehicle. For example, the system for your car alarm may get signals from the lock and the engine to activate the alarm. While there may be many ECUs in your car, there are a number of signs as to whether your unit may be damaged or not. We’ve gone into just a few below!

How might you know about a damaged ECU?

The first thing to look for is the engine light. This comes up on the dashboard and signals something is wrong within the car. The big reveal will be if the light stays on after resetting it.

Other symptoms that might indicate a bad ECU are that the car has entered emergency mode, the vehicle is shaking as you use it or that the engine no longer runs on all cylinders. One of these things may signal that an ECU is damaged. (Although by that point, you’ve probably sussed that there’s some kind of problem anyway!)

Your ECU can be damaged in a number of ways. Here are some of the most likely:

Water Damage

Water is a frequent cause of problems with ECUs because of the very nature of the machine. After an intense downpour, water ingress can cause some of the parts to malfunction. This is rare, as the ECU is usually protected by a watertight seal, but these can often erode and cause an issue.

Improper jump starting

Jump starting a car is a basic thing, but doing it incorrectly can cause an ECU malfunction. This is an easy mistake to make, especially as mechanics frequently restart motors. If you’re unsure about your used car, think about whether you’ve had to recently jump start the engine, and how likely it is that a check was missed, or something otherwise went wrong. It’s a particularly common issue with scrap cars. This vehicle may have been jump-started to get it going at a point before it was scrapped.

Broken starter

The starter sends the right amount of volts to the ECU. If the starter is bad or broken, it could end up sending the wrong voltage through, causing it to become faulty or malfunction. Becoming faulty could then cause other issues with your car. One for the mechanics here: you may experience issues if you have replaced the starter with one that isn’t compatible with your ECU. This would be a good place to start your investigations if you’re having ECU issues.

How much does an ECU cost?

We’ll be honest with you – they’re pretty expensive. ECUs vary in cost but they’re all well into the three figures. This usually depends on the make, model and age of your vehicle, but the cost can run from the hundreds to up to £1500. But the good thing is that faults don’t always require complete replacement ECUs. They can be electrical issues, wiring problems or incorrect compatibility.

If the ECU fault has become too much of an issue for your car, don’t worry. We’re used car experts here at RAW2K, and our online car auctions are always jam-packed with plenty of vehicles for your needs. From budgets to suit you, to manufacturers you can trust such as Ford, Vauxhall and Mercedes, why not check out our range today, and let’s find a motor that’s right for you.