The 3 main reasons for a defective ECU

The ECU (Engine Control unit) is one of the most important parts in modern cars. This part, also known as the engine control unit, plays a fundamental role in the control of the engine. Unfortunately, defects in this part are not uncommon.

In this blog we’ll discuss how the ECU operates, the symptoms of faulty ECU, the potential causes for failure and how our remanufacturing services can restore a faulty ECU.

How does an ECU operate?

simtec 71 defect

The ECU manages the control of the engine. The ECU is a computer that controls numerous processes, such as the throttle body, the moment of ignition and the pressure in turbo. On the basis of the data that the control unit receives from the various sensors, this information is processed in the so-called field of reference of the ECU.

The control unit converts this data into an action, namely the control of the actuators. The ECU has to process information from often more than a hundred different sensors. Think of information about the outside temperature, the position of the accelerator pedal, etc.

The main symptoms of a faulty ECU

But how can you tell that an ECU is defective? There are a number of symptoms with which a defect can be identified.

Some of the most well-known examples are: 

  • The engine failure light (MIL light) lights up on the instrument cluster.
  • The car goes into emergency mode. 
  • The car can shake or vibrate uncomfortably.

However, these observations don't provide a complete indication that the engine control unit is faulty. For this purpose the car will have to be diagnosed in the workshop by, among other things, making a test drive and viewing the live data.

Reading out fault codes can provide further detailed information about the defect, as certain fault codes are often found in combination with a certain engine control unit. For example, error code P0354 is common in the Siemens Simtec 71-series. This error code indicates problems with the control of the ignition coil.

defect delphi delco multec

3 main causes of a defective engine control unit

1. Burnout

This short circuit is often caused by external influences, such as the wrong start of the car. This is a cause that applies to a wide range of ECUs, although some engine controllers are more sensitive to this than others. An example of such a part is the Bosch EDC16C2, which has been used in several models of Mercedes.

2. Strong vibrations

Despite being mounted in a solid housing to protect the component, the vibrations endured over the years can still cause it to fail. This can cause the bond wires (or connecting wires) in the control unit to malfunction. The Magneti Marelli IAW 59F / 59M / 5AF / 5AM, which is mainly used in various Fiat models, is such an ECU that is sensitive to vibration.

3. High temperature

The location where the control unit is mounted plays an important role in this. The Delphi Delco Multec HSFI (learn more about the Delphi Multec HSFI) which has been used a lot in several Opel models is such an ECU, because it is mounted on the side of the cylinder head. Thanks to this heat, the bond wires are often the weak spot.

How should I get it fixed?

At ACTRONICS, we are the pioneers in remanufacturing. This means that we can take faulty parts, and directly fix and upgrade the offending component, providing your customers with a longer-lasting solution that costs everybody less.

Not only is this solution significantly cheaper than ordering and installing a brand new ECU, it also removes the need to throw out an old ECU, and buy a new one made from virgin materials. Opting for remanufacturing is the cheaper, greener and quicker option to restoring a faulty ECU back to new.

Ready to address your faulty ECU problem?


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Private individuals

If you’re a private individual, you can find your nearest ACTRONICS-approved Service Point to access our services. Simply search the map and quickly find a garage that will be able to help you fix your ECU fault.

Why choose ACTRONICS for your ECU repair service?

We are experts in testing and fixing instrument clusters and other car parts, and we're proud to offer a first-class service tailored for garages and dealerships. Here's what you get:

  • Remanufactured ECU unit ready in just 48 hours
  • A two-year warranty on all our parts
  • Quick, cost-effective, and top-quality service
  • Exclusive service for garages and dealerships
  • Expert guidance and support from our team

If you’re ready to fix your ECU fault, contact us today.