Airbag control unit with part number 8H0 959 655 F

What does the airbag control unit 8H0 959 655 F do?

The airbag control unit 8H0 959 655 F controls the restraint system (SRS) in Audi and monitors it during operation. In the event of an impact, it determines the position via the crash sensors and activates the intended airbags and seatbelt pretensioners within milliseconds.

If the unit detects a fault, it writes it to memory and lights the airbag warning light. After an accident it records crash data and remains locked; only the repair lifts the lock.

Why does the control unit 8H0 959 655 F fail?

The most common cause with the 8H0 959 655 F is considered to be crash data from an accident, even without an airbag having been triggered. Other causes include aged components, cold solder joints, moisture, corrosion and voltage spikes.

Crash data remains in the memory until it is removed during the repair; a normal diagnostic tool cannot do this.

Aged components and cold solder joints are hardly noticeable in everyday use and only show up through malfunctions.

Moisture and corrosion attack the plug connections, while voltage spikes arise, for example, from a weak battery or a jump start.

How can you tell that the 8H0 959 655 F is defective?

A defect on the 8H0 959 655 F becomes apparent when the airbag warning light does not go out, the instrument cluster shows an error message, the diagnostic tool cannot make contact, or the fault memory cannot be cleared.

These signs at a glance:

• airbag warning light on permanently or intermittently
• error message in the instrument cluster
• no connection to the control unit via the diagnostic tool
• fault memory cannot be cleared

If the unit is defective, airbags and seatbelt pretensioners may fail to deploy in an emergency. A warning light that does not go out must therefore be taken seriously.

Which vehicles is the 8H0 959 655 F fitted in?

In these vehicles the control unit 8H0 959 655 F is installed: Audi S4 B7 8H Convertible (2006-2009); Audi RS4 B7 8H Convertible (2007-2008).

The list of vehicles recorded for this number follows below.

• Audi S4 B7 8H Convertible (2006-2009)
• Audi RS4 B7 8H Convertible (2007-2008)

Comparing the part number on the label of the removed unit with this page only tells you about the identity of the unit. Having the fault memory read out before you take any action, on the other hand, shows whether the control unit is defective or whether cables or plugs are the cause.

For the same vehicles, we also repair control units with the part numbers 8H0 959 655 D, 8H0 959 655 G, 8H0959655E.

How does the repair of the 8H0 959 655 F work?

First have the fault memory read out along with the log, disconnect the battery, and only then remove the control unit 8H0 959 655 F. Then create the repair order online and send in the unit well packed. Processing at Airbag24 usually takes 3–4 working days.

First, Airbag24 checks the unit on the test bench. Afterwards, defective components are replaced, crash data is removed and a functional test is carried out.

The 3–4 working days apply only to this checking, repair and testing. The repaired unit then returns to you. Our repairs come with 2 years' statutory liability for defects. 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.

How does the control unit 8H0 959 655 F get to Airbag24?

One parcel is enough: send the 8H0 959 655 F yourself, or have it collected by UPS for an extra charge. It is returned via UPS after the repair.

Make sure to enclose the printed repair order and to pack the unit securely to withstand impact.