Airbag control unit with part number 402792B8

What does the airbag control unit 402792B8 do?

The airbag control unit 402792B8 runs the restraint system (SRS) in Renault vehicles. It evaluates crash sensors and, in an accident, causes the appropriate airbags and seatbelt pretensioners to trigger, within milliseconds.

In operation it monitors the entire system. If it detects a fault, it displays it via the airbag warning light. After an accident it stores crash data and locks itself.

Why does the control unit 402792B8 fail?

Stored crash data is the most common cause, even if no airbag has deployed, and a normal diagnostic tool cannot erase it. Aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes are also possible.

Voltage spikes arise, for example, from a weak battery or a jump start. With moisture and corrosion, by contrast, the focus is on the contacts at the plug connections.

Which cause applies in an individual case is clarified by the fault memory once it has been read out.

How can you tell that the 402792B8 is defective?

If the airbag warning light in the instrument cluster stays on permanently or intermittently, a defect is indicated. A fault message in the instrument cluster, a missing connection to the diagnostic tool or a fault memory that cannot be cleared are added signs.

Such a defect can mean that airbags and seatbelt pretensioners may fail to deploy in an emergency. The warning light makes it visible, so a prompt check is worthwhile.

Which vehicles is the 402792B8 fitted in?

The 402792B8 is fitted in the following vehicles: Renault Twingo II (2007-2014).

This breakdown shows the individual vehicles:

• Renault Twingo II (2007-2014)

Compare the part number on the removed unit with this page. Afterwards you know that it is the right unit. Having the fault memory read out is a separate step and important, because it shows whether the control unit is defective or whether a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 402787B3, 8200 491 652, 8200054938, 8200111668, 8200491655, 8200896811.

How does the repair of the 402792B8 work?

You read out the fault memory first and enclose the log. Then you disconnect the battery, remove the control unit and create a repair order online. Afterwards you pack the unit well and send it in.

Airbag24 checks the unit on the test bench, repairs defective components, erases stored crash data and carries out a function test. Processing usually takes 3–4 working days; 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 402792B8 get to Airbag24?

You ship the unit as a parcel or book a UPS collection for an extra charge. The return after the repair is likewise made by UPS.

With the printed repair order in the parcel and shockproof packing, the unit is well prepared.