Airbag control unit with part number 4H0959655F

What does the airbag control unit 4H0959655F do?

The airbag control unit 4H0959655F is the central control unit of the SRS for Audi. It evaluates the signals from the crash sensors, decides in a crash within milliseconds whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After an accident it stores crash data and locks itself.

The monitoring covers the entire wiring and the components in the system. If the unit detects a deviation, it records it in the fault memory and reports it via the airbag warning light in the instrument cluster.

The driver can therefore quickly see that something in the restraint system is not right.

Why does the control unit 4H0959655F fail?

The most common cause is crash data from an earlier accident, even if no airbag was triggered; a commercially available diagnostic tool cannot remove them. Further causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, as well as voltage spikes.

Crash data are created in the accident and remain in the unit. That no airbag was triggered changes nothing about this.

Electronics age, and connections can corrode or be impaired by moisture. Voltage spikes arise, for example, from a weak battery or a jump start.

How can you tell that the 4H0959655F is defective?

A defect in the 4H0959655F shows itself mainly through the airbag warning light in the instrument cluster, which lights up permanently or intermittently. An error message in the instrument cluster, a missing connection from the diagnostic tool to the control unit and a fault memory that cannot be cleared are also conspicuous.

• Airbag warning light, permanently or intermittently on
• Error message in the instrument cluster
• Diagnostic tool cannot find the control unit
• Fault memory cannot be cleared

In an emergency, airbags and seatbelt pretensioners may then not trigger.

Therefore, pay attention to these messages and have them checked promptly.

Which vehicles is the 4H0959655F fitted in?

The airbag control unit 4H0959655F is fitted in these vehicles: Audi A6 C7 4G Facelift (2014-2018) and C7 4G (2010-2014).

The list summarises the vehicles that are stored in our data for this part number.

• Audi A6 C7 4G Facelift (2014-2018)
• Audi A6 C7 4G (2010-2014)

Compare the part number on the label of the removed unit with this page, to make sure that it is the right unit. Additionally have the fault memory read out beforehand, because only its log shows whether the control unit itself is defective or whether a connector or a cable causes the problem.

For the same vehicles, we also repair control units with the part numbers 285010856, 4G0959655A, 4G0959655B, 4H0 959 655 C, 4H0959655B, 4H0959655H.

How does the repair of the 4H0959655F work?

First you read out the fault memory and attach the log, then you disconnect the battery and only afterwards remove the control unit 4H0959655F. Then create a repair order online and send in the well-packed unit. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components, erases the stored crash data and then carries out a function test. Afterwards the unit goes 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 4H0959655F get to Airbag24?

You send the control unit 4H0959655F as a parcel, or arrange a UPS collection for an extra charge. After the repair, Airbag24 brings the unit back to you by UPS.

The printed repair order goes into the parcel, and the unit is packed shock-proof.