Airbag control unit with part number A2049014604

What does the airbag control unit A2049014604 do?

The airbag control unit A2049014604 is the central control unit of the restraint system (SRS) in Mercedes-Benz. It processes signals from the crash sensors, evaluates an impact within milliseconds and controls the triggering of airbags and seatbelt pretensioners.

The unit detects faults continuously and reports them via the airbag warning light. After an accident it stores crash data and locks itself.

The monitoring runs in the background while you are on the road.

Why does the control unit A2049014604 fail?

The most common trigger is crash data after an accident, even without an airbag being triggered; an ordinary diagnostic tool cannot remove it. Other causes include ageing components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data in the memory is not the same as damage. Airbag24 erases it during the repair.

The other causes act over time: electronics age, solder joints can go cold, moisture attacks contacts, and voltage spikes occur, for example, with a weak battery or jump-starting.

How can you tell that the A2049014604 is defective?

A defect shows itself mainly through the airbag warning light in the instrument cluster. Fault messages and disrupted communication with the diagnostic tool may also occur.

Typical signs are:

• Airbag warning light on permanently or intermittently
• Fault message in the instrument cluster
• Diagnostic tool cannot reach the control unit
• Fault memory cannot be cleared

In an emergency, the airbags and seatbelt pretensioners may then not be triggered. A prompt check brings clarity.

Which vehicles is the A2049014604 fitted in?

The control unit A2049014604 is fitted in these vehicles: Mercedes-Benz C-Class S204 Estate (2007-2014), W204 Saloon (2007-2014) and C204 Coupé (2011-2015).

These vehicles are on record:

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

You carry out the comparison with the label of the removed unit using this page. It confirms the correct unit, but says nothing about a defect. For that, have the fault memory read out beforehand, because the log shows whether the control unit or 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 A2049014604 work?

Have the fault memory read out first and enclose the log. Then disconnect the battery and only afterwards remove the control unit. Processing at Airbag24 usually takes 3–4 working days.

Then create the repair order online and send the unit in well packed. Airbag24 checks it on the test bench, replaces defective components, deletes the crash data and carries out a function test before your own unit is 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 A2049014604 get to Airbag24?

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

Enclose the printed repair order in the parcel and pack the unit shock-proof.