Airbag control unit with part number A0004461742

What does the airbag control unit A0004461742 do?

The airbag control unit A0004461742 controls the restraint system (SRS) of Mercedes-Benz. It evaluates the signals from the crash sensors and, in an accident, decides within a few milliseconds which airbags and seatbelt pretensioners to trigger.

Outside an accident the unit monitors the entire system continuously. If it detects a fault, it indicates this via the airbag warning light in the instrument cluster. After an accident it stores crash data and locks itself.

The manufacturer's number Bosch 0285020601 is also printed on the housing. This information helps to match it with the removed unit.

Why does the control unit A0004461742 fail?

The most common cause is crash data stored after an accident, even if no airbag has fired, and a standard diagnostic tool cannot erase it. Further causes are aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, for example from a weak battery or a jump-start.

Crash data remains in memory until it is removed during repair. A control unit that shows no deployment after a collision may still be affected, because the sensors have already registered an impact.

The other causes can develop gradually. Moisture and corrosion attack the contacts, and solder joints can loosen under vibration over the years without being visible from the outside.

How can you tell that the A0004461742 is defective?

A defect shows up as the airbag warning light in the instrument cluster lighting up permanently or intermittently, and as a fault message in the display. In addition, the diagnostic tool does not connect to the control unit, or the fault memory cannot be cleared.

If the unit is defective, airbags and seatbelt pretensioners may not trigger in an emergency. For that reason, do not ignore the light, even if the vehicle otherwise runs normally.

The warning light is the most important signal the vehicle gives you. Do not wait for the next inspection to have the fault memory read; have it read promptly as soon as the light comes on.

Which vehicles is the A0004461742 fitted in?

According to our current data, this allocation applies to Mercedes-Benz. The airbag control unit A0004461742 is fitted in these vehicles: Mercedes-Benz Vito W639 (2003-2014); Mercedes-Benz Viano W639 (2003-2014); Mercedes-Benz V-Class W639 (2003-2014).

The following overview names the models for which A0004461742 is stored in our data.

• Mercedes-Benz Vito W639 (2003-2014)
• Mercedes-Benz Viano W639 (2003-2014)
• Mercedes-Benz V-Class W639 (2003-2014)

Two steps help with the allocation. First, compare the part number on the label of the removed unit with this page; this only ensures that you have the correct unit. Second, have the fault memory read beforehand, because only that result shows whether the control unit is defective or whether a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 0285010349, 285001448, 285001449, 285010033, 285010054, 285010224.

How does the repair of the A0004461742 work?

First have the fault memory read and enclose the log with the unit. Then disconnect the battery and remove the control unit. Next, create a repair order online and send in the well-packed unit.

At Airbag24 the unit is examined on the test bench, defective components are repaired and stored crash data is erased. A function test follows, and then your own unit is sent back to you. Processing at Airbag24 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 A0004461742 get to Airbag24?

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

Enclose a printed copy of the repair order with the parcel and protect the unit with shock-proof packaging before handing it over.