Airbag control unit with part number A2049013202

What does the airbag control unit A2049013202 do?

The airbag control unit A2049013202 manages the restraint system (SRS) in Mercedes-Benz. From the signals of the crash sensors it works out within milliseconds which airbags and seatbelt pretensioners are to be triggered, and it monitors the system continuously. If it detects a fault, it reports it via the airbag warning light.

After an accident the unit stores crash data and locks itself.

In everyday use it stays unobtrusive, but it keeps working in the background so that it can decide without delay in an emergency.

Why does the control unit A2049013202 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. Other causes are ageing electronic components, cold solder joints, moisture and corrosion on plug connectors, and voltage spikes, for example from a weak battery or jump-starting.

A standard diagnostic tool cannot remove crash data. The other causes act over a longer period: electronic components age, solder joints can break, and moisture attacks plug connectors.

How can you tell that the A2049013202 is defective?

A defect shows first on the airbag warning light in the instrument cluster. In an emergency, the airbags and seatbelt pretensioners may then fail to deploy.

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

The warning light is a warning signal from the system. It indicates a finding that does not stay hidden and therefore requires a check.

Which vehicles is the A2049013202 fitted in?

The A2049013202 is fitted in these vehicles: Mercedes-Benz C-Class S204 Estate (2007-2014), W204 Saloon (2007-2014) and C204 Coupé (2011-2015).

The vehicles affected are recorded in this list:

• Mercedes-Benz C-Class S204 Estate (2007-2014)
• Mercedes-Benz C-Class W204 Saloon (2007-2014)
• Mercedes-Benz C-Class C204 Coupé (2011-2015)

Compare the part number on the label of the removed unit with this page. This only shows that it is the right unit. Have the fault memory read out beforehand, because only this log reveals 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 2048709426, 5WK44740, A204 870 68 26, A204 901 26 04, A204 901 35 02, A2048208285.

How does the repair of the A2049013202 work?

First have the fault memory read out and attach the log. Then disconnect the battery, remove the control unit and create a repair order online. You send in the well-packed unit, Airbag24 tests it, replaces defective components, erases crash data and tests the function; afterwards your own unit is returned to you.

This sequence serves safety and cannot be reversed. At Airbag24 processing usually takes 3–4 working days, and this period covers testing, repair and function testing only.

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 A2049013202 get to Airbag24?

You send the unit in as a parcel or book a UPS collection for an extra charge. After the repair, your own unit comes back to you by UPS.

The printed repair order goes into the parcel, and the unit is packed shock-proof.