Airbag control unit with part number 4E0 959 655 K

What does the airbag control unit 4E0 959 655 K do?

The airbag control unit 4E0 959 655 K is the central SRS control unit for Audi. It evaluates the signals from the crash sensors, decides within milliseconds in an accident which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

Faults are reported via the airbag warning light in the instrument cluster. Monitoring covers the sensors, the airbags and the seatbelt pretensioners together with their wiring.

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

Why does the control unit 4E0 959 655 K fail?

Stored crash data is the most common cause, even if no airbag was triggered. A normal diagnostic tool cannot erase this data. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

Airbag24 erases the crash data during the repair. That is part of processing the unit.

The other causes relate to the condition of the electronics and their surroundings. Components age, solder joints can go cold, moisture attacks plug connectors, and voltage spikes stress the components.

How can you tell that the 4E0 959 655 K is defective?

A defect in the 4E0 959 655 K shows up as the airbag warning light staying on permanently or intermittently, and as a fault message in the instrument cluster. Furthermore, the diagnostic tool cannot establish a connection to the control unit, and the fault memory remains.

• The airbag warning light stays on permanently or intermittently.
• A fault message appears in the instrument cluster.
• The diagnostic tool gets no connection to the control unit.
• The fault memory cannot be cleared.

In the event of such a fault, the airbags and seatbelt pretensioners may fail to trigger. Please have the warning checked promptly to find out what it means.

Which vehicles is the 4E0 959 655 K fitted in?

The assignment depends on the part number 4E0 959 655 K. The control unit 4E0 959 655 K is fitted in these vehicles: Audi S8 D3 (2006-2008) and D3 Facelift (2008-2010); Audi A8 D3 4E (2002-2005) and D3 4E Facelift (2005-2010).

The overview lists the vehicles recorded for this part number.

• Audi S8 D3 (2006-2008)
• Audi S8 D3 Facelift (2008-2010)
• Audi A8 D3 4E (2002-2005)
• Audi A8 D3 4E Facelift (2005-2010)

Compare the part number on the label of the removed unit with this page. That only confirms it is the right unit. Also have the fault memory read out beforehand, as only that shows whether the control unit itself is affected or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 0285001672, 0285001705, 285001512, 285001705, 4E0 959 655 H, 4E0910655.

How does the repair of the 4E0 959 655 K work?

Processing at Airbag24 usually takes 3–4 working days. Beforehand, have the fault memory read out and enclose the printout. Then disconnect the battery and only then remove the control unit. Afterwards create a repair order online and send in the carefully packed unit.

Airbag24 checks the unit on the test bench, repairs defective components, erases the stored crash data and carries out a function test. The unit then goes back to you.

This time applies solely to checking, repairing and testing there.

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 4E0 959 655 K get to Airbag24?

You send the control unit 4E0 959 655 K as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Put the printed repair order into the parcel and pack the unit shock-proof.