Airbag control unit with part number A2048709326

What does the airbag control unit A2048709326 do?

The airbag control unit A2048709326 is the central control unit of the restraint system (SRS) of Mercedes-Benz. It evaluates the signals from the crash sensors, decides within milliseconds in an accident which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

To do this, the unit checks its components continuously and shows faults via the airbag warning light. In normal operation nothing of this is visible.

If an accident occurs, the control unit stores crash data and locks itself. This lock ends only with the repair.

Why does the control unit A2048709326 fail?

A failure of the A2048709326 most often has its cause in crash data stored after an accident, even if no airbag was triggered. A normal diagnostic tool cannot erase it.

The crash data stay in the unit until they are deliberately removed. Airbag24 erases them during the repair.

Other causes lie in the electronics themselves: aged components, cold solder joints, and moisture or corrosion at plug connections. Voltage spikes, for example from a weak battery or jump-starting, are also possible.

How can you tell that the A2048709326 is defective?

The airbag warning light in the instrument cluster stays on at the A2048709326 permanently or intermittently, and an error message appears in the instrument cluster. The diagnostic tool cannot establish a connection to the control unit, and the fault memory cannot be cleared.

The warning light can be the first visible sign. Do not dismiss it as a trifle, because it affects the entire restraint system.

In an emergency, airbags and seatbelt pretensioners may not trigger. A prompt check provides clarity.

Which vehicles is the A2048709326 fitted in?

The airbag control unit A2048709326 is fitted in these vehicles: Mercedes-Benz C-Class S204 Estate (2007-2014), W204 Saloon (2007-2014) and C204 Coupé (2011-2015).

The vehicle list, against which you can match your car, follows below.

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

Read out the fault memory before removal. That shows whether the control unit is really defective or whether a plug or cable is the cause. Then compare the part number on the label of the removed unit with this page.

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 A2048709326 work?

Read out the fault memory before removal, disconnect the battery, remove the A2048709326 and create a repair order online. Processing at Airbag24 usually takes 3–4 working days.

Attach the fault memory log to the unit before sending it in well packed.

At Airbag24 the control unit is checked on the test bench, defective components are repaired, the crash data are erased, and a function test follows.

Afterwards, your own unit goes 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 A2048709326 get to Airbag24?

You send the control unit A2048709326 as a parcel or book UPS collection for an extra charge. After the repair, Airbag24 sends the unit back to you by UPS.

Put the printed repair order in the parcel and pack the control unit shockproof.