Airbag control unit with part number A1779006003

What does the airbag control unit A1779006003 do?

The airbag control unit A1779006003 controls the restraint system (SRS) for Mercedes-Benz. In an accident it evaluates the signals from the crash sensors and decides within milliseconds which airbags and seatbelt pretensioners are triggered.

It also monitors the system during operation. Any faults it finds are reported via the airbag warning light in the instrument cluster. The manufacturer part number Bosch 0285014882 is additionally printed on the housing.

After an accident the unit stores crash data and locks itself. This state is part of the control unit's behaviour and shows up in the vehicle through the warning indicator.

Why does the control unit A1779006003 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, for example from a weak battery or jump-starting.

The stored crash data remains in the unit. Ordinary reading out does not remove it, so the fault persists.

The other causes can develop over a longer period. Ageing components, damp or corroded contacts and cold solder joints lead to faults that recur.

How can you tell that the A1779006003 is defective?

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

The warning light is the signal you should pay attention to. As long as it is on, the airbags and seatbelt pretensioners may not trigger in an emergency.

If the connection to the diagnostic tool is missing, the cause may lie in the control unit or in the wiring. Only a read-out of the fault memory gives a reliable answer.

Which vehicles is the A1779006003 fitted in?

The control unit A1779006003 is fitted in these vehicles: Mercedes-Benz A-Class W177 (from 2018).

The vehicles on record for this part number are listed here:

• Mercedes-Benz A-Class W177 (from 2018)

Compare the part number on the label of the removed unit with this page. That way you know you have the right unit. Have the fault memory read out beforehand as well, as it shows whether the control unit or a plug or cable is causing the problem.

For the same vehicles, we also repair control units with the part numbers 0 285 015 019, 0285020871, A 177 900 03 04, A1779027906, A2479013703, A2479018801.

How does the repair of the A1779006003 work?

First read out the fault memory and attach the log. Then disconnect the battery and only then remove the control unit. Next create a repair order online; Airbag24 usually needs 3–4 working days for processing.

Pack the unit well and send it together with the repair order. The sequence must be followed for safety reasons.

Airbag24 checks the unit on the test bench, repairs defective components, erases the stored crash data and carries out a function test. Your own unit is then returned 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 A1779006003 get to Airbag24?

You send the unit in as a parcel or book UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Put the printed repair order in the parcel. Pack the control unit shock-resistant.