Audi TTS 8J9 Roadster airbag control unit repair

What is an Audi TTS 8J9 Roadster airbag control unit?

In the Audi TTS 8J9 Roadster, the airbag control unit is the central unit of the restraint system (SRS). It reads the crash sensors. In an accident it decides within milliseconds which airbags and seatbelt pretensioners fire.

The unit works constantly in the background. It checks the whole system and shows faults via the airbag warning light. If an accident occurs, it stores crash data and locks itself. Besides the control unit, the restraint system also includes sensors, airbag modules and seatbelt pretensioners. The control unit connects these parts with one another and evaluates their signals.

It is fitted in the Audi TTS 8J9 Roadster (2009 to 2014). The unit is made by Bosch.

Why is the Audi TTS 8J9 Roadster airbag control unit defective?

Most often the cause is crash data left behind by an accident. This applies even if no airbag deployed. An ordinary diagnostic tool does not delete it. Other possible causes are aged components, cold solder joints, moisture, corrosion on connectors and voltage spikes.

Electronic components age over the years. Solder joints can turn cold and lose contact. Water and corrosion attack the connectors. A weak battery or jump-starting can produce voltage spikes.

You can usually recognise a fault by the airbag warning light, which stays on permanently. The fault memory cannot be cleared. Sometimes the unit does not respond to the diagnostic tool at all. Have the system checked in that case, because a locked unit will not fire in an emergency.

Common error codes for Audi TTS 8J9 Roadster airbag control unit repair

The codes in the Audi TTS 8J9 Roadster show in which area of the airbag system a fault lies. They concern internal faults of the unit, the supply voltage and individual squib circuits.

These codes occur frequently on this vehicle, shown here with their meaning.

• 65535 → Internal control unit fault
• 00532 → Supply voltage too low, intermittent
• 00588 → Driver airbag squib circuit, resistance fault
• 00590 → Passenger airbag squib circuit, second stage
• 01217 → Driver-side side airbag squib circuit, resistance fault
• 01218 → Passenger-side side airbag squib circuit, resistance fault

A diagnostic tool reads the codes from the fault memory. A single code alone does not reliably point to a defective control unit. Connectors, wiring or an airbag module are just as likely causes. The inspection reveals the real cause. If you have a diagnostic report, please enclose it with the repair order if possible.

What part numbers are available for the Audi TTS 8J9 Roadster airbag control unit repair?

You read the part number from the label on the unit. It determines the exact version. Depending on equipment and year of manufacture, units of the same model series in the Audi TTS 8J9 Roadster carry different numbers.

You will find known numbers in this list. It is not complete.

• 8J0959655Z5K
• 8J0959655Z5P (Bosch)

Hold the number of your unit next to the list. This only tells you that it is the matching unit. Whether there is a fault is only clarified by the fault memory read-out or the inspection at Airbag24.

The route to the repair is short. First read out the fault memory and disconnect the battery. Remove the control unit. Create a repair order online and send in the unit. Airbag24 usually inspects, repairs and tests it within 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.