Airbag control unit with part number A2048706926

What does the airbag control unit A2048706926 do?

The airbag control unit A2048706926 is the central control unit of the restraint system (SRS) in Mercedes-Benz. It evaluates the signals from the crash sensors, decides in a crash whether the airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After a crash it locks itself; the lock is only lifted by the repair.

The unit stores faults in the fault memory and reports them via the instrument cluster.

Because several protective functions depend on this one control unit, a defect affects the entire restraint system.

Why does the control unit A2048706926 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.

The crash data remains stored in the unit until a repair removes it.

The other causes at a glance:

• ageing electronic components
• cold solder joints
• moisture and corrosion at plug connectors
• voltage spikes, for example from a weak battery or a jump start

How can you tell that the A2048706926 is defective?

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

The airbag warning light is the most obvious indication. Permanent lighting and intermittent lighting are both findings that require a check.

If no connection to the diagnostic tool can be established, or the fault memory remains full despite an attempt to clear it, the control unit or its connection is affected. Airbags and seatbelt pretensioners may then fail to deploy in an emergency.

Which vehicles is the A2048706926 fitted in?

The control unit A2048706926 is fitted in these vehicles: Mercedes-Benz C-Class S204 Estate (2007-2014), W204 Saloon (2007-2014) and C204 Coupé (2011-2015).

You will find the associated models here:

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

Comparing the part number on the label with this page only confirms that it is the right unit. This comparison does not clarify the cause. Have the fault memory read out beforehand, because only the log shows 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 A2048706926 work?

You have the fault memory read out and attach the log, then disconnect the battery and only then remove the control unit A2048706926. Next, create a repair order online and send in the unit, well packed. Processing at Airbag24 usually takes 3–4 working days.

At Airbag24 the unit is checked on the test bench, defective components are replaced, crash data is erased and a function test is carried out. 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 A2048706926 get to Airbag24?

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

Enclose the printed repair order and pack the control unit shockproof.