Airbag control unit with part number 985101957R

What does the airbag control unit 985101957R do?

For Renault, the airbag control unit 985101957R is the central control unit of the restraint system (SRS). It evaluates the signals from the crash sensors, decides in a split second in an accident which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It shows faults via the airbag warning light.

Monitoring runs in the background. Faults end up in the fault memory, which a workshop or a diagnostic tool can read out.

After an accident, it stores crash data and locks itself. The lock is only lifted by the repair.

Why does the control unit 985101957R fail?

The most common cause on the 985101957R is crash data stored after an accident, even if no airbag has deployed. It cannot be erased with a normal diagnostic tool, but Airbag24 deletes it during the repair. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

Crash data is a record kept by the control unit of the accident. The fact that no airbag has deployed does not change this record.

Over time, electronic components lose reliability. Cold solder joints are connections on the circuit board that are not properly bonded and can therefore cause contact problems.

Moisture and corrosion attack the contacts at plug connectors and disrupt signal transmission. Voltage spikes, for example from a weak battery or a jump start, put additional strain on the electronics.

How can you tell that the 985101957R is defective?

The airbag warning light in the instrument cluster lights up on the 985101957R, either permanently or intermittently. This is accompanied by a fault message in the instrument cluster, a diagnostic tool with no connection to the control unit, and a fault memory that cannot be cleared.

Pay particular attention to these signs:

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

In an emergency, the airbags and seatbelt pretensioners may then fail to deploy. Take the warning light seriously and have the system checked.

Which vehicles is the 985101957R fitted in?

The control unit 985101957R is fitted in these vehicles: Renault Mégane IV (from 2016). This list shows you whether your vehicle is one of them.

These vehicles are listed here:

• Renault Mégane IV (from 2016)

Compare the part number on the label of the removed unit with this page; this only makes sure that you have the right unit in front of you. Also have the fault memory read out before removal, because only this result 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 985104870R, 985107896R, 985108011R.

How does the repair of the 985101957R work?

First have the fault memory read out and enclose the log, then disconnect the battery and remove the control unit. Then create a repair order online and send the unit in, well packed. Airbag24 checks the 985101957R on the test bench, replaces defective components, deletes the stored crash data and carries out a function test; processing at Airbag24 usually takes 3–4 working days.

The order of these steps is for safety on the vehicle, so please follow it exactly.

Airbag24 deletes the crash data as part of the repair.

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 985101957R get to Airbag24?

You send the control unit 985101957R in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

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