Audi RS5 8F Convertible airbag control unit repair

What is an Audi RS5 8F Convertible airbag control unit?

The Audi RS5 8F Convertible airbag control unit is the central control unit of the restraint system (SRS). It evaluates the signals from the crash sensors, decides within milliseconds in an accident whether to deploy airbags and seatbelt pretensioners, and continuously monitors the system.

The control unit runs a self-test as soon as the engine starts. It checks whether the sensors, squib circuits and its own electronics are working properly. Only when everything is in order does the airbag warning light go out. The control unit is fitted in the Audi RS5 8F Convertible (2012 to 2015) and comes from Bosch.

If the control unit reports a fault, the warning light stays on. After an accident it stores crash data and locks itself.

Why is the Audi RS5 8F Convertible airbag control unit defective?

The most common cause is crash data stored after an accident, even if no airbag deployed. Other causes include aged electronic components, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

The stored crash data cannot be erased with an ordinary diagnostic tool. The control unit therefore stays locked, even if the vehicle was repaired long ago. A control unit can also fail without an accident: over the years electronic components age, solder joints become brittle, and moisture can attack connectors. Voltage spikes, for example from a weak battery or a jump start, put additional strain on the electronics.

Typical signs are an airbag warning light that stays on permanently, a fault memory that cannot be cleared, or a diagnostic tool that cannot connect to the control unit. If you notice any of these signs, a diagnosis is worthwhile before taking further steps.

Common error codes for Audi RS5 8F Convertible airbag control unit repair

The error codes of this control unit relate to internal control unit faults, the voltage supply and the squib circuits of the airbags. Which code is stored in the fault memory depends on the damage involved.

The following list shows error codes that occur on Audi RS5 8F Convertible airbag control units, with their meaning:

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

Error codes are read out with a diagnostic tool. A code alone does not reliably show that the control unit is defective. Connectors, wiring or an airbag module can also be the cause. Only testing clarifies where the fault actually lies.

What part numbers are available for the Audi RS5 8F Convertible airbag control unit repair?

The part number is printed on the control unit's label and determines its exact version. Within a model series there are different numbers depending on equipment and year of manufacture.

The following list contains known part numbers for Audi RS5 8F Convertible airbag control units, without any claim to completeness:

• 8K0959655B (Bosch)
• 8K0959655G
• 8K0959655J

Compare the number on your unit with this list. This only confirms that it is the right unit. Whether it is defective is shown only by reading out the fault memory or by testing.

Here is how to proceed with the repair: have the fault memory read out, disconnect the battery and remove the control unit. Then create a repair order online and send in the unit. Processing at Airbag24, covering checking, repairing and testing, usually takes 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.