Audi RS3 8VS Saloon airbag control unit repair

What is an Audi RS3 8VS Saloon airbag control unit?

In the Audi RS3 8VS Saloon, the airbag control unit is the central unit of the restraint system (SRS). It reads the crash sensors, decides within milliseconds of an impact which airbags and seatbelt pretensioners fire, and continuously monitors the entire system. It reports anything unusual to you through the airbag warning light.

The Audi RS3 8VS Saloon model series (2017 to 2020) works with this unit. In the background it constantly tests itself as well as the sensors, squib circuits and power supply. If it finds an irregularity, it stores an entry in the fault memory and switches on the warning light.

If there has been an accident, the control unit records crash data and locks itself. This first shows up in the instrument cluster: the light does not go out again.

Why is the Audi RS3 8VS Saloon airbag control unit defective?

The first thing you usually notice is the airbag warning light staying on permanently. Most often the cause is crash data from an accident, even if no airbag deployed; other causes include aged components, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

How you notice a problem: the light stays on, the fault memory cannot be reset, or the diagnostic tool finds no contact with the control unit at all. All three symptoms can have the same root cause.

The most common cause is crash data left in the unit by an accident. An ordinary diagnostic tool cannot remove it, even if the airbags stayed quiet.

Without an accident, the electronics fail through ageing of the components or cold solder joints. Moisture getting in makes connectors corrode. Voltage spikes also do damage, for example from a weak battery or a jump start.

Common error codes for Audi RS3 8VS Saloon airbag control unit repair

The codes in the Audi RS3 8VS Saloon point to different classes of fault: internal faults of the control unit, insufficient supply voltage, or irregularities in the squib circuits of the airbags. They are stored in the fault memory and can be read out with a diagnostic tool.

The following codes are known for this vehicle:

• 65535 → General internal fault in the control unit
• 00532 → Supply voltage too low, intermittent
• 00588 → Driver airbag squib circuit, resistance fault
• 00590 → Passenger airbag squib circuit, fault detected
• 01217 → Front driver-side airbag squib circuit, resistance fault
• 01218 → Front passenger-side airbag squib circuit, resistance fault

The codes are read out with a diagnostic tool. A single entry does not reliably show that the control unit is defective, because connectors, wiring or an airbag module are just as likely to be the cause. Only testing brings clarity.

What part numbers are available for the Audi RS3 8VS Saloon airbag control unit repair?

On the label of the control unit you will find the part number, which defines its exact version. Depending on equipment and year of manufacture, the numbers differ within a model series, so you should look at the label before sending the unit in.

These part numbers are known for the Audi RS3 8VS Saloon, although the list is not complete:

• 5Q0959655AB
• 5Q0959655AD
• 5Q0959655K
• 5Q0959655M

Compare the number of your unit with the list. This only ensures that it is the right unit. Whether there is a defect is shown only by reading out the fault memory or by testing.

The route to repair: have the fault memory read out, disconnect the battery and remove the control unit. Then you create a repair order online and send in the unit. At Airbag24, testing, repairing and checking usually take 3–4 working days.

The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.