Audi A3 8VS Saloon airbag control unit repair

What is an Audi A3 8VS Saloon airbag control unit?

In the Audi A3 8VS Saloon, the airbag control unit is the SRS hub, the superordinate unit of the entire restraint system. It receives the signals from the crash sensors and, in an impact, decides within milliseconds which airbags and seatbelt pretensioners deploy. Once it has registered an accident, it stores crash data and locks itself.

The unit is fitted in the Audi A3 8VS Saloon (2013 to 2020). While you are driving, it continuously monitors sensors, squib circuits and wiring. If it detects a deviation, it switches on the airbag warning light in the instrument cluster and records the fault in the fault memory.

Because the restraint systems rely on this unit to deploy in an emergency, you should not ignore an illuminated airbag warning light.

Why is the Audi A3 8VS Saloon airbag control unit defective?

If the airbag warning light of your Audi A3 8VS Saloon stays on permanently, the most common cause is crash data left behind by an earlier accident, even if no airbag was deployed. Ageing electronic components, cold solder joints, moisture and corrosion on connectors, or voltage spikes, for example from a weak battery or jump-starting, are also possible causes.

What you notice as a driver usually looks the same: the warning light stays on, the fault memory cannot be reset, or the diagnostic tool cannot connect to the control unit at all. You cannot tell from the outside which cause lies behind it.

Crash data is particularly stubborn. An ordinary diagnostic tool cannot remove it, which is why the unit stays locked even if the vehicle was long since repaired after the accident. With moisture or ageing components, on the other hand, only testing in the laboratory shows where the fault lies.

Common error codes for Audi A3 8VS Saloon airbag control unit repair

The codes that a Audi A3 8VS Saloon reports point to faults in the power supply, in the squib circuits of the airbags or in the control unit itself. They are read from the fault memory with a diagnostic tool.

Below you will find codes that occur on this model. They concern internal faults of the unit, the supply voltage and individual squib circuits.

• 65535 → Control unit internally defective
• 00532 → Supply voltage too low, sporadic
• 00588 → Driver airbag squib circuit, resistance fault
• 00590 → Passenger airbag squib circuit, fault
• 01217 → Driver-side side airbag squib circuit, resistance fault
• 01218 → Passenger-side side airbag squib circuit, resistance fault

Please note: a single code does not yet prove a defect in the control unit. Connectors, wiring or an airbag module may just as well be the trigger. Where the fault really lies is determined by the test. Please include the diagnostic report with your unit.

What part numbers are available for the Audi A3 8VS Saloon airbag control unit repair?

You will find the part number on the label of your control unit, and it shows the exact version. Depending on equipment and year of manufacture, different numbers are in circulation within the Audi A3 8VS Saloon model range.

Known part numbers for this vehicle are listed below, although the list does not claim to be complete.

• 5Q0959655AD
• 5Q0959655BT
• 5Q0959655JZ00

Hold the number on your unit next to this list. This only ensures that it is the right unit. Whether it is defective only becomes clear once the fault memory has been read out or the unit has been tested.

The route to repair looks like this: first have the fault memory read out, disconnect the battery from the vehicle electrical system and then remove the control unit. Afterwards you create a repair order online and send the unit in. Testing, repairing and checking at Airbag24 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.