Airbag control unit with part number A2079012500

What does the airbag control unit A2079012500 do?

The airbag control unit A2079012500 is the control unit of the restraint system (SRS) for Mercedes-Benz. It processes the messages from the crash sensors and determines in an emergency, within milliseconds, which airbags and seatbelt pretensioners fire.

Monitoring runs in the background for as long as the vehicle is in operation. If the unit finds a fault in the system, it stores a fault entry and shows the fault via the airbag warning light.

After an accident, the control unit writes crash data to its memory and locks itself. The lock is only lifted by the repair.

Why does the control unit A2079012500 fail?

Most often the cause lies in crash data stored after an accident, even if no airbag has deployed. Further triggers are ageing electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, for example from a weak battery or a jump start.

Crash data cannot be erased with a normal diagnostic tool. The fault therefore persists, even though nothing more is visible on the vehicle from the outside. Airbag24 erases this data during the repair.

The other causes develop gradually. Electronics age, solder joints can remain cold, and moisture finds its way into plugs. Faults of this kind cannot be reliably identified from the outside.

How can you tell that the A2079012500 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently. In addition, a fault message appears in the instrument cluster, the diagnostic tool has no connection to the control unit, and the fault memory cannot be cleared.

If the light comes on, have the system checked promptly and do not wait. A warning of this kind should be taken seriously.

In an emergency, airbags and seatbelt pretensioners may then fail to deploy. The vehicle continues to drive, but the warning remains justified.

Which vehicles is the A2079012500 fitted in?

The A2079012500 is fitted in these vehicles: Mercedes-Benz E-Class C207 Coupé (2009-2016) and A207 Convertible (2010-2017).

The following list shows the vehicles assigned to this part number.

• Mercedes-Benz E-Class C207 Coupé (2009-2016)
• Mercedes-Benz E-Class A207 Convertible (2010-2017)

Two checks will help you. Comparing the part number on the label of the removed unit with this page confirms that it is the correct unit. Have the fault memory read out beforehand; only this shows whether the control unit is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 2079011700, A2078203226, A2079010100, A212 901 85 08.

How does the repair of the A2079012500 work?

First have the fault memory read out and enclose the log, then disconnect the battery and remove the control unit. Next, create a repair order online and send the unit in well packed. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 examines the unit on the test bench, replaces defective components, erases stored crash data and carries out a function test. Only then is your own unit sent back to you.

The sequence is fixed for safety reasons: the control unit may only be removed after the battery has been disconnected.

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 A2079012500 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.

Enclose the printed repair order and pack the control unit shock-resistant so that it arrives undamaged.