Compare BMW 4 Series ECU repair quotes from specialist garages

Looming hundreds of feet up in Munich's skyline is BMW's headquarters, a vast and impressive building designed to look like four engine cylinders - the configuration that drove much of the brand's early success.

BMW has come a long way since 1927, when it produced its first car, the Dixi, shortly to be renamed the BMW 3/15. In 2022, it was awarded 'Best Manufacturer' at the AutoCar Britain's Best Car Awards, and the same year, it triumphed at the WhatCar? Awards, winning more accolades than any other brand. The M5 special edition, celebrating 20 years of BMW motorsport, is one of the rarest M automobiles in the world.

See how BMW's maintenance prices compare to Audi and Mercedes in this guide.

ECU stands for engine control unit, sometimes referred to as the engine control module (ECM). This component ensures your car's engine runs smoothly by, for example, determining the amount of fuel that goes into the cylinders. You can find out more about how it works here.

Signs of a faulty ECU include misfires, the check engine light, starting problems, and engine surges or lags. ECU testing and repairs can help you work out the cause of the problem, such as faulty wiring or a bad sensor.

ECU testing uses a diagnostic tool known as an OBD scanner, which extracts information from the car's computer and allows the technician to check fault codes.

Can an ECU be repaired? Most of the time, the answer is yes; the ECU can be reprogrammed or repaired. The same applies to water damaged ECUs, as long as the damage is minimal. Some technicians may offer mobile ECU repairs at a location that's convenient for you.