Airbag control unit with part number A2179008101

What does the airbag control unit A2179008101 do?

The airbag control unit A2179008101 is the central control unit of the restraint system (SRS) for Mercedes-Benz. It evaluates the signals from the crash sensors and decides within milliseconds in an accident which airbags and seatbelt pretensioners are triggered. It also monitors the system continuously and reports faults via the airbag warning light.

After an accident, the control unit stores crash data and locks itself. The entire deployment depends on this evaluation, which is why the unit plays a central role in the vehicle.

Why does the control unit A2179008101 fail?

For the control unit A2179008101, the most common cause is crash data stored after an accident, even if no airbag has deployed; a standard diagnostic tool cannot erase it. Other causes include ageing electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes.

The unit records crash data as soon as it registers an accident. Their presence does not mean that an airbag has deployed.

The other causes are general in nature. Electronics age over time, solder joints can go cold, and moisture and corrosion attack plug connections. Voltage spikes, for example from a weak battery or jump-starting, additionally stress the electronics.

How can you tell that the A2179008101 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and an error message appears in the instrument cluster. In addition, a diagnostic tool gets no connection to the control unit A2179008101, and the fault memory cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then fail to deploy. If you notice these signs, have the system checked promptly.

The warning light shows the defect even if nothing else is noticeable while driving.

Which vehicles is the A2179008101 fitted in?

Whether your vehicle fits can be checked with the part number A2179008101. The airbag control unit A2179008101 is fitted in these vehicles: Mercedes-Benz S-Class C217 Coupé (2014-2020) and A217 Convertible (2014-2020).

The list names the vehicles for which this part number is recorded at Airbag24.

• Mercedes-Benz S-Class C217 Coupé (2014-2020)
• Mercedes-Benz S-Class A217 Convertible (2014-2020)

Both steps will help you. Compare the part number on the label of the removed unit with this page, and then you know it is the right unit. Also have the fault memory read out, because only that shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers A2179008302, A2229000303, A2229009908, A2229013503.

How does the repair of the A2179008101 work?

First have the fault memory of the control unit A2179008101 read out and attach the log. Only after disconnecting the battery do you remove the unit. Next, create a repair order online and send in the well-packed unit.

Airbag24 checks the unit on the test bench, repairs defective components, erases crash data and tests the function. After that, your own, repaired unit is returned to you.

Processing at Airbag24 takes 3–4 working days. This period covers only checking, repairing and testing.

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 A2179008101 get to Airbag24?

You send the control unit A2179008101 in 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 into the parcel and pack the unit so that it is shockproof.