Airbag control unit with part number 4M0959655BH

What does the airbag control unit 4M0959655BH do?

The airbag control unit 4M0959655BH is the central control unit of the restraint system (SRS) for Audi. It evaluates the crash sensors, decides in an accident within milliseconds on the triggering of airbags and seatbelt pretensioners, and monitors the entire system.

If it detects a fault, it indicates this via the airbag warning light in the instrument cluster.

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

Why does the control unit 4M0959655BH fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. For this control unit, deleting the crash data is often not possible; if you want it deleted, contact Airbag24 briefly before sending the unit in. Other causes are aged components, cold solder joints, moisture or corrosion at plug connections, and voltage spikes.

These causes come into question in detail:

• aged electronic components,
• cold solder joints,
• moisture and corrosion at plug connections,
• voltage spikes, for example from a weak battery or jump-starting.

Which cause applies to your unit can only be clarified by inspection.

How can you tell that the 4M0959655BH is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently. A fault message, connection problems with the diagnostic tool and a fault memory that cannot be emptied may also accompany it.

As long as the fault persists, airbags and seatbelt pretensioners may not trigger in an emergency.

A fault can also occur only sporadically. Reading out the fault memory still records which messages have occurred.

Which vehicles is the 4M0959655BH fitted in?

The overview is only a first guide. The airbag control unit 4M0959655BH 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).

These models are known to us with 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 it is the correct unit. Also have the fault memory read out, because only the result shows whether the control unit itself is defective or whether a connector or a 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 4M0959655BH work?

Start by reading out the fault memory, whose log you attach, and then disconnect the battery. Only then do you remove the control unit, create the repair order online and send in the unit well packed. Airbag24 checks it on the test bench, repairs defective components and carries out a function test before the unit is returned to you.

If you want the crash data deleted, contact Airbag24 briefly before sending the unit in.

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 4M0959655BH get to Airbag24?

You send the control unit as a parcel or commission a UPS collection for an extra charge. Afterwards Airbag24 returns the unit by UPS.

The printed repair order goes into the parcel, and the packaging must be shock-resistant.