Airbag control unit with part number 680850800D

What does the airbag control unit 680850800D do?

The airbag control unit 680850800D is the central control unit of the restraint system (SRS) for Renault. It evaluates signals from the crash sensors, decides within milliseconds in a crash which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It indicates faults via the airbag warning light; after a crash it stores crash data and locks itself.

While driving, the evaluation runs in the background. If there is a genuine impact, the control unit initiates the appropriate deployment.

Why does the control unit 680850800D fail?

Crash data stored on the control unit 680850800D after an accident is the most common cause, even when no airbag has deployed; a standard diagnostic tool cannot erase it. Other possible causes are aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, for example from a weak battery or jump-starting.

Crash data is the record of what the sensors measured during an impact. As long as it remains in the memory, the fault persists.

The other causes develop over a longer period. Electronics age, solder joints can go cold, and moisture attacks the plug contacts.

How can you tell that the 680850800D is defective?

A defect shows when the airbag warning light in the instrument cluster stays on permanently or intermittently and a fault message appears in the instrument cluster. The diagnostic tool gets no connection to the control unit 680850800D, or the fault memory cannot be cleared. In this state, airbags and seatbelt pretensioners may not deploy in an emergency.

The warning light is the system's own message and not a minor signal. When it lights up, have the fault memory checked.

Which vehicles is the 680850800D fitted in?

The airbag control unit 680850800D is fitted in these vehicles: Renault Mégane IV (from 2016).

The list shows the vehicles for which we have this control unit on record.

• Renault Mégane IV (from 2016)

Match the part number on the label of the removed unit with this page. This only confirms that it is the correct unit. Whether the control unit itself is defective or a plug or cable is the cause is shown only by the fault memory, which you should have read out beforehand.

For the same vehicles, we also repair control units with the part numbers 985101957R, 985104870R, 985107896R, 985108011R.

How does the repair of the 680850800D work?

First have the fault memory read out and attach the log to the unit, then disconnect the battery; only then remove the control unit 680850800D. Then create a repair order online and send the well-packed unit in. At Airbag24 the processing time is usually 3–4 working days.

The sequence is mandated for safety reasons. Only once the battery is disconnected do you remove the control unit from the vehicle.

Airbag24 tests the unit on the test bench, replaces defective components, erases stored crash data and carries out a function test. 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 680850800D get to Airbag24?

You send the control unit 680850800D as a parcel or book a UPS collection for an extra charge; after the repair Airbag24 returns it to you by UPS. Enclose the printed repair order in the parcel and pack the unit shock-resistant.

A sturdy carton with sufficient padding protects the control unit during transport. The padding also prevents it from shifting inside the carton.