Airbag control unit with part number 4KE959655D

What does the airbag control unit 4KE959655D do?

The airbag control unit 4KE959655D takes over control of the restraint system (SRS) for Audi. It processes the signals from the crash sensors, decides within milliseconds in an emergency which airbags and seatbelt pretensioners trigger, and monitors the system continuously. After an accident it stores crash data and locks itself.

The monitoring covers the entire system, so faults are detected and displayed. They are reported via the airbag warning light in the instrument cluster.

Why does the control unit 4KE959655D fail?

The most common cause is crash data that is stored in the memory after an accident, even if no airbag has deployed; a normal diagnostic tool cannot clear it. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

Crash data arises as soon as the unit registers an accident, regardless of whether an airbag deploys. That is why the fault display remains for as long as the entries are in the unit.

Other causes include components that age over time, solder joints that have gone cold, and moisture or corrosion at plug connectors. Voltage spikes, for example from a weak battery or a jump start, can also disturb the electronics.

How can you tell that the 4KE959655D is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, a fault message is shown in the instrument cluster, the diagnostic tool cannot reach the control unit, and the fault memory cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then fail to deploy.

A lit warning symbol is the most obvious sign. The control unit switches on the warning light as soon as it detects a fault in the system, even if the vehicle continues to drive normally.

If the connection to the diagnostic tool fails, or the fault memory remains after being read out, this strengthens the suspicion. A check then shows whether the control unit is affected.

Which vehicles is the 4KE959655D fitted in?

The airbag control unit 4KE959655D 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 of vehicles for this part number follows here:

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

Comparing the part number on the label with this page confirms that you have the right unit. The condition of the control unit itself is shown only by reading out the fault memory before removal: it reveals whether the control unit or a connector 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 4KE959655D work?

First have the fault memory read out and attach the log to the order. Then disconnect the battery before you remove the control unit. Create the repair order online and send the unit in well packed. Airbag24 needs 3–4 working days for checking, repair and testing.

Airbag24 checks the unit on the test bench, repairs the defective components, deletes the stored crash data and carries out a function test. Afterwards the unit is sent 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 4KE959655D get to Airbag24?

Either you send the unit as a parcel, or you arrange a UPS collection for an extra charge. The return after the repair is likewise made by UPS.

The printed repair order goes into the parcel, and you pack the unit shock-proof.