Airbag control unit with part number A2079011800

What does the airbag control unit A2079011800 do?

The airbag control unit A2079011800 is the central control unit of the restraint system (SRS) at Mercedes-Benz. It evaluates the signals from the crash sensors and decides in a collision, within milliseconds, which airbags and seatbelt pretensioners are triggered.

In addition it monitors the entire system continuously. If it detects a fault, it reports it via the airbag warning light in the instrument cluster. After a collision the unit stores crash data and locks itself.

Many protective functions run through this unit. A failure therefore affects the entire safety equipment of the vehicle, not just a single indicator.

Why does the control unit A2079011800 fail?

On the A2079011800 the most common cause after a collision is stored crash data, even if no airbag has deployed. A standard diagnostic tool cannot erase it. Further triggers are aged electronic components, cold solder joints, corrosion at plug connections caused by moisture, and voltage spikes such as with a weak battery or jump-starting.

The fact that crash data cannot be erased with an ordinary tool means: Airbag24 removes it during the repair. The other causes develop over a longer period, for example when moisture attacks a plug contact.

Crash data therefore arises even when no airbag has deployed. The data remains stored in the control unit after the collision.

How can you tell that the A2079011800 is defective?

The airbag warning light in the instrument cluster lights up on the A2079011800 permanently or intermittently. In addition there is a fault message in the instrument cluster, a diagnostic tool without a connection to the control unit and a fault memory that cannot be cleared. In such a case the airbags and seatbelt pretensioners may not be able to deploy in an emergency.

The warning light is the hint the system gives itself. Anyone who sees it should have the fault memory read out promptly.

A missing access with the diagnostic tool is a second finding, which you will notice directly when reading out.

Which vehicles is the A2079011800 fitted in?

The A2079011800 belongs to Mercedes-Benz vehicles and is fitted in these vehicles: Mercedes-Benz E-Class C207 Coupé (2009-2016) and A207 Convertible (2010-2017).

The list of stored vehicles follows for an overview.

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

Compare the part number on the label of the removed unit with this page. This only ensures that it is the correct unit. Have the fault memory read out before removal, because only this log shows whether the control unit is defective or whether a plug or a 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 A2079011800 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only then remove the A2079011800. Next you create a repair order online and send the unit in well packed.

Airbag24 checks the unit on the test bench and replaces defective components. The team then erases the stored crash data and carries out a function test.

Processing at Airbag24 itself usually takes 3–4 working days.

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 A2079011800 get to Airbag24?

You send the control unit A2079011800 as a parcel, or you 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.