Airbag control unit with part number 8F0959655A000

What is the function of the airbag control unit 8F0959655A000?

The airbag control unit 8F0959655A000 is the central control module for the occupant protection system, specifically installed in the Audi A5 8F Cabrio. It analyzes data from crash sensors, deploys airbags and seatbelt pretensioners in the event of a collision, and stores relevant crash data in its internal memory.

Technically, this control unit is responsible for informing the entire vehicle network about the status of the airbag system. It communicates continuously with other control units in the vehicle, ensuring that all components of the restraint system—such as airbags and seatbelts—are fully operational.

Proper functionality is essential for vehicle safety, as a malfunction could prevent the safety systems from deploying correctly in an emergency.

What types of failures occur in 8F0959655A000?

The most common issues with the 8F0959655A000 control unit involve internally stored crash data after an accident, which can prevent further use. Other causes include age-related failures of electronic components such as processors or capacitors, as well as damage caused by moisture or excessive heat inside the vehicle.

A very common reason for failure is the storage of crash data. Even after a minor accident—for example, when only the knee airbag deploys—the control unit locks itself internally and cannot be reset. As a result, the airbag warning light remains illuminated permanently.

Electronic faults on the circuit board are also typical. These often manifest as error code 65535, indicating an internal fault within the control unit. Errors such as B200049 or A00049-89 likewise point to an internal problem requiring component-level repair.

It should be noted that similar models, such as the Audi A5/S5 (8T), may use related part numbers like 8K0959655, 8K0959655J, or devices marked 5WK43748/43749. These parts can exhibit comparable fault patterns.

How do you recognize a fault in the 8F0959655A000 control unit?

A defective 8F0959655A000 airbag control unit primarily shows up as a permanently lit or intermittently flashing airbag warning light on the instrument cluster. Often, the control unit cannot be read using a diagnostic tool, or error codes such as 65535 (control unit failure) appear and cannot be cleared.

The most noticeable sign is the activated airbag warning light. It does not turn off after starting the engine or suddenly illuminates during driving, frequently accompanied by heat buildup.

Another clear indication is when the workshop is unable to establish communication with the airbag control unit. The device no longer responds to diagnostic requests, making precise fault analysis impossible.

In some cases, additional symptoms seemingly unrelated to the airbag system emerge. Customers report a non-functioning clock in the cockpit or a blinking engine check light, suggesting a deeper communication issue within the vehicle’s electrical system caused by the faulty airbag control unit.

In which models is 8F0959655A000 installed?

The airbag control unit with part number 8F0959655A000 is specifically designed for Audi vehicles. It is mainly used in the Audi A5 Cabrio of the 8F series, both in pre-facelift and facelift models.

At Airbag24, we repair this control unit for the following vehicles:

Audi: A5 8F Cabrio (2007–2011) and A5 8F Cabrio Facelift (2011–2016).

To ensure maximum compatibility, it is advisable to verify the part number directly on the removed control unit, as variations may exist depending on equipment levels and model years.

How is the 8F0959655A000 repaired?

Repair of the control unit at Airbag24 involves precise diagnostics, addressing the root cause of the fault at the component level, and a final functional test. Depending on the nature of the issue, stored crash data is erased, defective components such as processors are replaced, and the software is reprogrammed.

After removal from the vehicle and shipment to Airbag24, the control unit undergoes an initial inspection. During this stage, the reported fault is verified, and the unit is examined for external damage, such as moisture or improper repair attempts.

The actual repair focuses on identifying and resolving the underlying cause. For stored crash data, the control unit’s internal memory is professionally reset. In cases of hardware defects, faulty electronic components on the circuit board are located and replaced with new, high-quality parts.

After successful repair, the control unit undergoes a comprehensive test on a simulation bench to ensure the proper functioning of all systems. Each repair is covered by 2 years' statutory liability for defects.