Airbag control unit with part number 4M0959655R

What does the airbag control unit 4M0959655R do?

In the restraint system (SRS) of Audi, the airbag control unit 4M0959655R is the central evaluation unit. It receives the signals from the crash sensors, determines in a crash within milliseconds which airbags and seatbelt pretensioners fire, and checks the system without interruption.

It reports faults via the airbag warning light in the instrument cluster. The light is therefore the visible sign that something in the system is wrong.

After an accident the unit stores crash data and locks itself.

Why does the control unit 4M0959655R fail?

The most common cause with the 4M0959655R is crash data stored after an accident, even if no airbag was deployed. A normal diagnostic tool cannot erase this data. Further causes can be aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The unit stores the incident regardless of whether an airbag was deployed. Crash data is therefore a cause of its own, not a consequence of a deployment.

Voltage spikes arise, for example, from a weak battery or a jump start. Only the inspection shows which cause applies in the individual case.

How can you tell that the 4M0959655R is defective?

The airbag warning light in the instrument cluster lights up with the 4M0959655R permanently or intermittently. In addition come a fault message in the instrument cluster, no connection between the diagnostic tool and the control unit, and a fault memory that cannot be cleared.

If these signs appear, have the system checked promptly. In an emergency, airbags and seatbelt pretensioners may not deploy, and early inspection is exactly what guards against that.

Which vehicles is the 4M0959655R fitted in?

The control unit 4M0959655R 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).

The list below shows the vehicles recorded for this part number.

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

Compare the part number on the label of the removed unit with this page, so that you can be sure you have the correct unit. Have the fault memory read out beforehand, because only this result shows whether the control unit is defective or whether a plug or cable is the cause.

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 4M0959655R work?

First have the fault memory read out and attach the record. Then disconnect the battery and only afterwards remove the control unit 4M0959655R. Next create a repair order online and send in the well-packed unit.

Airbag24 checks the unit on the test bench and replaces defective components. Airbag24 also erases stored crash data before a function test follows. The unit is then returned to you.

Processing at Airbag24 usually takes 3–4 working days. 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 4M0959655R get to Airbag24?

You can send the control unit 4M0959655R in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it via UPS.

Place the printed repair order in the parcel and pack the unit so that it is shock-resistant.