Airbag control unit with part number A2048707026

What does the airbag control unit A2048707026 do?

In the Mercedes-Benz vehicle, the airbag control unit A2048707026 controls the restraint system (SRS). It reads the crash sensors and determines in an accident which airbags and seatbelt pretensioners are triggered; this decision is made within fractions of a second. In addition, it monitors the system continuously and shows faults via the airbag warning light.

Monitoring runs in the background without interruption, and every detected fault ends up in the fault memory. It stays there for a later readout.

If an accident occurs, the unit records crash data and locks itself. This is where the repair comes in, because only then are the crash data removed from the unit.

Why does the control unit A2048707026 fail?

Stored crash data is the most common cause: it remains in the unit after an accident, even if no airbag was triggered, and a normal diagnostic tool cannot erase it. Other causes include aged components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, for example from a weak battery or a jump start.

Such entries do not disappear on their own. They remain in the unit until they are erased during a repair, and they affect the evaluation of every later diagnostic attempt.

The other causes concern ageing and contacts inside the unit. Without reading the fault memory they can hardly be narrowed down, and they can overlap.

How can you tell that the A2048707026 is defective?

Typical signs are an airbag warning light in the instrument cluster that stays on permanently or intermittently, an error message in the instrument cluster, a diagnostic tool without connection to the control unit, and a fault memory that cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

The signs at a glance:

• Airbag warning light in the instrument cluster stays on permanently or intermittently
• Error message in the instrument cluster
• Diagnostic tool receives no connection to the control unit
• Fault memory cannot be cleared

The warning light makes the fault visible. Only the readout shows whether the control unit itself or a plug is behind it.

Which vehicles is the A2048707026 fitted in?

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

The following overview shows the assigned vehicles:

• 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 ensures that it is the right unit. Also have the fault memory read out. Only the protocol shows whether the control unit is defective or a plug or a 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 A2048707026 work?

Processing at Airbag24 usually takes 3–4 working days. Before that, have the fault memory read out, enclose the protocol and disconnect the battery before removing the control unit. Then create a repair order online and pack the unit well before sending it in.

Airbag24 checks the unit on the test bench, repairs defective components, erases the stored crash data and carries out a function test. Afterwards the 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 A2048707026 get to Airbag24?

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

Put the printed repair order into the parcel and pack the unit shock-proof.