Airbag control unit with part number A1179003801

What does the airbag control unit A1179003801 do?

The airbag control unit A1179003801 controls the restraint system (SRS) of Mercedes-Benz. It reads the crash sensors, determines the triggering of the airbags and seatbelt pretensioners within milliseconds in an accident, and monitors the system permanently.

Faults in the system are shown by the unit via the airbag warning light. Monitoring continues even when the vehicle is not being moved.

After an accident the control unit stores crash data and locks itself. The lock remains in place until a repair lifts it.

Why does the control unit A1179003801 fail?

The most common cause is crash data stored after an accident, even without an airbag being triggered, which a normal diagnostic tool cannot erase. Other causes include ageing electronics, cold solder joints, moisture and corrosion at plugs, and voltage spikes.

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

The crash data remains in the control unit until Airbag24 removes it during the repair. Which of the other causes applies only becomes clear from the test of the unit.

How can you tell that the A1179003801 is defective?

On the A1179003801 the airbag warning light stays on permanently or intermittently, a fault message appears in the instrument cluster, the diagnostic tool receives no connection to the control unit, and the fault memory cannot be cleared.

The warning light is the clearest sign you will receive while driving. It can burn constantly or light up only now and then, and both point to a fault in the system.

In case of a defect, airbags and seatbelt pretensioners may not be able to trigger in an emergency. A warning light that comes on therefore calls for prompt clarification.

Which vehicles is the A1179003801 fitted in?

The control unit A1179003801 is fitted in the following vehicles: Mercedes-Benz CLA-Class C117 Saloon (2013-2019).

Below you will find the vehicles we have on record for this part number.

• Mercedes-Benz CLA-Class C117 Saloon (2013-2019)

Compare the part number on the label of the removed unit with this page. This only ensures that you have the correct unit. In addition, have the fault memory read out beforehand, because only this result 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 285011863, 285013862, A117 900 58 00, A1179001802, A1179009200, A1179011700.

How does the repair of the A1179003801 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only after that remove the control unit A1179003801. Next, create a repair order online and send the unit in well packed.

Airbag24 tests the unit on the test bench, replaces defective components, erases the crash data and carries out a function test. Your own unit is then returned to you.

Processing at Airbag24 usually takes 3–4 working days. 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 A1179003801 get to Airbag24?

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

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