Airbag control unit with part number 4M0959655L

What does the airbag control unit 4M0959655L do?

The airbag control unit 4M0959655L controls the restraint system (SRS) in vehicles from Audi. In an impact it evaluates the crash sensors and determines within milliseconds which airbags and seatbelt pretensioners are triggered. In normal operation it monitors the entire system and reports faults via the airbag warning light.

Most of the time the unit works in the background, checking the supply voltage, the connections and the connected components. The number Bosch 0285014795 is also printed on the housing.

An accident causes the unit to store crash data and lock itself.

Why does the control unit 4M0959655L fail?

The most common cause is stored crash data that arises after an accident, even if no airbag has triggered; a normal diagnostic tool cannot erase it. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes from a weak battery or jump-starting. Airbag24 erases the crash data during the repair.

The entry in the memory remains until the repair removes it. Reading it out changes nothing about that.

The other causes develop over time: components age, solder joints become brittle, and moisture attacks the contacts.

How can you tell that the 4M0959655L is defective?

A fault shows up as the airbag warning light in the instrument cluster, which lights up permanently or intermittently, and as a fault message in the instrument cluster. The diagnostic tool may then find no connection to the control unit, and the fault memory cannot be erased. In an emergency, airbags and seatbelt pretensioners may then not trigger.

The warning light is the indication the system gives itself, and it deserves attention even if the vehicle otherwise seems to run normally.

Which cause lies behind it is shown only by reading out the fault memory.

Which vehicles is the 4M0959655L fitted in?

The airbag control unit 4M0959655L 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 following list 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. That only ensures that it is the correct unit. Also have the fault memory read out, because only this result shows whether the control unit is defective or whether a plug 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 4M0959655L work?

First have the fault memory read out and attach the log to the unit. Then disconnect the battery and only then remove the control unit. Then create a repair order online and send the unit in well packed.

At Airbag24 the unit is examined on the test bench, defective components are replaced, stored crash data is erased and finally a function test is carried out. Processing for checking, repair and function testing at Airbag24 is usually planned at 3–4 working days. Your own unit is then returned 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 4M0959655L get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 returns it to you by UPS.

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