Computers and Electronics

Is your Audi showing unexpected warning lights, failing to start after a control-unit replacement or losing a comfort function? The fault may involve an ECU, another control module, its wiring or the vehicle’s power supply.

Modern Audi vehicles use several connected control units. A fault in one module can therefore cause errors in other systems as well.

At Donkers VAG Parts, you will find genuine used ECUs, control units and electronic parts for Audi models. The parts come from vehicles dismantled in-house. This means information about the donor vehicle, fitted equipment and part identification is often available.

ECUs and control modules

Depending on current stock, this category may include:

• engine ECUs;
• transmission control units;
• gateway modules;
• body control modules;
• comfort control units;
• door control modules;
• Haldex control units;
• airbag modules;
• parking-assistance modules;
• camera and radar modules;
• MMI and infotainment units.

Two control units may use the same housing while having different internal hardware, software or enabled functions.

Do not rely on appearance alone. Compare the complete part number, including the suffix, as well as the hardware and software versions where available.

Coding, adaptation and component protection

Installing a used control unit is often only the first step. Depending on the module and vehicle, further work may be required.

This can include:

• coding;
• adaptation;
• software parameterisation;
• immobiliser matching;
• component-protection removal;
• calibration;
• transfer of vehicle-specific data.

An engine ECU may still be linked to the immobiliser of the donor vehicle. MMI units, comfort modules and other electronic parts may also be restricted by component protection.

Without the correct adaptation, a working control unit may cause warning messages, remain partly disabled or prevent the engine from starting.

Check the fault before replacement

A fault code does not always prove that the named control unit is defective.

Similar faults can be caused by:

• low battery voltage;
• poor earth connections;
• damaged wiring;
• corroded connectors;
• a failed sensor;
• communication faults in the vehicle network.

Before replacing a control unit, check its power supply, earth connections and communication with the rest of the vehicle.

This helps avoid replacing a module when the actual fault is elsewhere.

Hardware, software and vehicle equipment

Control units are often linked to a specific vehicle specification. Equipment such as parking sensors, cameras, navigation, seat functions or driver-assistance systems can affect the required version.

Before ordering, compare:

• the complete Audi part number;
• suffix letters;
• hardware version;
• software version;
• engine code;
• gearbox code;
• vehicle equipment and PR codes;
• connector layout and pin arrangement.

For camera, radar and driver-assistance modules, calibration may also be required after installation.

Safety-related control units

Airbag modules and other restraint-system components require particular care. A used module may contain stored crash data or may not match the fitted airbag system.

The part number, software version and vehicle equipment must be checked before installation. Work on airbag systems should be carried out with suitable diagnostic equipment and by someone familiar with the system.

Finding the correct control unit

The complete part number is the main starting point, but it may not be enough on its own. A matching basic number can still have a different suffix, software level or vehicle assignment.

Looking for an engine ECU, door module, MMI unit or another electronic part for your Audi? Start by comparing the complete part number, hardware version and vehicle specification. If you are unsure, send us the vehicle identification number and the identification details from the existing unit. We can then check which version may be suitable for your vehicle.