Airbag control unit with part number A2139007220

What does the airbag control unit A2139007220 do?

The airbag control unit A2139007220 evaluates the crash sensor signals in the restraint system (SRS) for Mercedes-Benz. In an emergency, it decides within milliseconds which airbags and seatbelt pretensioners trigger. At the same time, it monitors all components of the system and reports faults via the airbag warning light.

Monitoring runs throughout the entire journey. The control unit compares the measured values with stored set values and records every deviation in the fault memory.

After an accident, the control unit stores crash data and locks itself, regardless of whether an airbag has deployed.

Why does the control unit A2139007220 fail?

The most common cause is crash data that remains in the control unit after an accident, even without an airbag having deployed. A normal diagnostic tool does not erase it. Other causes include ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or a jump start.

That crash data is stored in the unit cannot be seen from the outside of the vehicle. For this very reason, it is worth looking into the control unit before other components come under suspicion.

The other causes develop over years. Components age, solder joints give way with temperature changes, and moisture or corrosion weaken the contact at plug connections.

How can you tell that the A2139007220 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, a fault message appears in the instrument cluster, the diagnostic tool receives no connection to the control unit, and the fault memory cannot be cleared. Then airbags and seatbelt pretensioners may possibly not trigger in an emergency.

The signs appear singly or in combination:

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

The warning light is the clearest sign. It must be heeded, even if it only comes on now and then.

Which vehicles is the A2139007220 fitted in?

The A2139007220 is fitted in these vehicles: Mercedes-Benz E-Class S213 Estate (2016-2023) and W213 Saloon (2016-2023).

The following list names the vehicles that Airbag24 has assigned to this part number.

• Mercedes-Benz E-Class S213 Estate (2016-2023)
• Mercedes-Benz E-Class W213 Saloon (2016-2023)

Compare the part number on the label of the removed unit with this page. This only makes sure that you have the correct unit. Have the fault memory read out beforehand, because only this log 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 A213 900 46 25, A213 900 88 22, A213 900 88 28, A2139007105, A2139010104.

How does the repair of the A2139007220 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only then 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 checks the control unit on the test bench, replaces defective components, erases the stored crash data and carries out a function test. Afterwards your own unit is returned to you.

This sequence is for your safety. The 3–4 working days refer only to checking, repairing and testing at Airbag24.

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 A2139007220 get to Airbag24?

You send the unit 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.