Airbag control unit with part number A2218704787

What does the airbag control unit A2218704787 do?

The airbag control unit A2218704787 is the restraint system (SRS) control unit at Mercedes-Benz. It evaluates the crash sensors and, in a crash, decides within milliseconds which airbags and seatbelt pretensioners are triggered.

During operation it checks the components of the system continuously. If it detects a deviation, it shows this via the airbag warning light in the instrument cluster.

After an accident the unit stores crash data and locks itself. Only the repair lifts this lock.

The housing additionally bears the manufacturer number Bosch 0285001995.

Why does the control unit A2218704787 fail?

For the control unit A2218704787, the most common cause is stored crash data after an accident, even if no airbag was triggered. Other causes are ageing components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data cannot be cleared with a normal diagnostic tool. Airbag24 therefore removes it during the repair.

The other causes develop more gradually. Electronic components age, solder joints can be cold, and moisture attacks plug connections. Voltage spikes, for example from a weak battery or when connecting a jump start, also occur.

How can you tell that the A2218704787 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently if there is a fault on the A2218704787. In addition, a fault message appears in the instrument cluster and the diagnostic tool gets no connection to the control unit.

The fault memory also cannot be cleared. In this condition airbags and seatbelt pretensioners may possibly not deploy in an emergency.

Which vehicles is the A2218704787 fitted in?

The control unit A2218704787 is fitted in these vehicles: Mercedes-Benz S-Class W221 Saloon (2005-2013).

Here follows the list of vehicles for which this unit is registered.

• Mercedes-Benz S-Class W221 Saloon (2005-2013)

You can compare the part number on the label of the removed unit with this page yourself. It only confirms that it is the right unit. Have the fault memory read out beforehand, since only that result 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 2218200226, 2218704887, 285001896, 285001995, A0048201326, A2218200985.

How does the repair of the A2218704787 work?

First have the fault memory read out, then disconnect the battery and only then remove the control unit. Next, create a repair order online and send in the unit well packed. At Airbag24, checking, repair and function testing take 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components, clears the crash data and carries out a function test. Attach the read-out log to the parcel. Your own, repaired unit then comes 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 A2218704787 get to Airbag24?

You send the control unit A2218704787 as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 sends the unit back by UPS.

Put the printed repair order into the parcel and make sure the unit is shock-proof.