Airbag control unit with part number 4M0959655H

What does the airbag control unit 4M0959655H do?

The airbag control unit 4M0959655H is the evaluation unit of the restraint system (SRS) in Audi vehicles. It evaluates the signals from the crash sensors, decides in an accident on the triggering of airbags and seatbelt pretensioners, and monitors the system in the background.

If it detects a fault, it displays it via the airbag warning light. After a collision it stores crash data and locks itself.

Why does the control unit 4M0959655H fail?

The most common cause is crash data from an accident that stays stored when no airbag was triggered. A standard diagnostic tool cannot clear it; Airbag24 deletes the data during the repair. On the 4M0959655H, ageing components, cold solder joints, moisture at plug connections and voltage spikes are also added.

The other causes at a glance:

• ageing of electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes from a weak battery or a jump start

How can you tell that the 4M0959655H is defective?

A defect becomes visible when the airbag warning light is on, a fault message appears in the instrument cluster, the diagnostic tool does not establish a connection to the control unit, or the fault memory cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then not trigger. The light is therefore not a cosmetic flaw but a sign that you must take seriously.

A fault memory that cannot be cleared also remains a sign of a fault that must be checked.

Which vehicles is the 4M0959655H fitted in?

The control unit 4M0959655H is fitted in these vehicles: Audi Q7 4M (2015-2019) and 4M Facelift (2019-2024); Audi SQ7 4M (2016-2019) and 4M Facelift (from 2019). Whether your car is among them is shown by a look at the vehicle registration document.

The vehicles in the overview:

• Audi Q7 4M (2015-2019)
• Audi Q7 4M Facelift (2019-2024)
• Audi SQ7 4M (2016-2019)
• Audi SQ7 4M Facelift (from 2019)

On the one hand, you compare the part number on the label of the removed device with this page, which only confirms the right device. On the other hand, have the fault memory read out before removal, because only it shows whether the control unit is defective or whether a plug or cable is affected.

For the same vehicles, we also repair control units with the part numbers 4KE959655B, 4KE959655J, 4KE959655L, 4M0 959 655 AF, 4M0 959 655 G, 4M0 959 655 K.

How does the repair of the 4M0959655H work?

Processing at Airbag24 usually takes 3–4 working days. Beforehand you have the fault memory read out, enclose the log, disconnect the battery and remove the control unit 4M0959655H, before you create the repair order online.

The route is by parcel, or UPS collects the device for an extra charge. On the test bench the device is examined, defective components are replaced, the crash data deleted and a function test carried out.

Afterwards your own device goes back 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 4M0959655H get to Airbag24?

The route is either by parcel, or UPS collects the control unit 4M0959655H for an extra charge. The return after the repair is also handled by UPS.

The printed repair order belongs in the parcel, and the device is packed shock-proof.