Compare ECU Repair Deals Near You

How Much Does an ECU Repair Cost?

An ECU repair typically costs between £150 and £400, while a replacement ECU, including coding it to your car, usually costs £500 to £1,500 or more.

The price depends on whether your existing unit can be repaired or needs replacing, your make and model (prestige makes can sometimes cost more), whether the ECU needs coding and the labour to remove and refit it.

The garage will usually need to find the cause of the fault first, as the same symptoms are often caused by a faulty sensor or another part. If your engine management light is on, you can book a diagnostic check to get started.

Typical UK costs based on published industry estimates as of 8th October 2026. Prices are representative figures only as costs vary depending on your make and model, the parts used and your chosen garage. Enter your reg and postcode to compare labour rates from local garages.

What Does an ECU Do?

The engine control unit (ECU) is a small computer that manages your engine. It uses sensors to control things like fuel injection, ignition timing and emissions, keeping your car running smoothly.

ECU remapping, which changes your engine's performance settings, is a different job from an ECU repair.

Can an ECU Be Repaired, or Does It Need Replacing?

A damaged ECU can often be repaired, depending on how much damage there is.

Some repairs mean removing the ECU and sending it to a specialist. Depending on the fault and whether parts are available, an ECU repair can take anywhere from a few hours to a couple of days.

If your ECU needs replacing, the new unit (even a used one) has to be programmed to your car, including its immobiliser, before it will work properly.

Your chosen garage will be able to advise on the best course of action once they have inspected your vehicle.

What Causes an ECU to Fail?

ECUs can fail for several reasons, including:

• Water getting in, or corrosion

• Voltage spikes, for example from jump-starting or a failing alternator

• Damaged wiring or short circuits

• Software problems

Warning Signs of a Faulty ECU

You might have a problem with your ECU if you notice any of the following:

• The engine management light comes on

• The engine stalls or misfires

• Worse fuel economy than usual

• Difficulty starting the car

• Rough running or poor performance

These symptoms can also be caused by a faulty sensor or another part, so the garage will check those first.

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