Airbag control unit with part number 9666411980

What does the airbag control unit 9666411980 do?

The control unit 9666411980 is the evaluation unit of the airbags in the restraint system (SRS) of Citroën. It takes in the values from the crash sensors and, in a crash, decides within milliseconds which airbags and seatbelt pretensioners fire. While driving, it monitors the system and reports faults via the airbag warning light.

Monitoring covers sensors, wiring and triggers. Faults found are stored by the unit in the fault memory.

After an accident, it stores crash data and then locks itself.

Why does the control unit 9666411980 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. A normal diagnostic tool cannot erase this data; Airbag24 erases it during the repair. Aged components, moisture and voltage spikes also play a role.

Crash data already arise from registering an event. An airbag does not need to have deployed for that.

Aged electronics and cold solder joints put long-term strain on the unit. Moisture and corrosion at plug connections disrupt the contacts.

Voltage spikes occur, for example, with a weak battery or when a jump start is connected.

How can you tell that the 9666411980 is defective?

The airbag warning light lights up permanently or intermittently, and an error message appears in the instrument cluster. The diagnostic tool cannot reach the control unit, and the fault memory remains. In an emergency, airbags and seatbelt pretensioners may then fail to deploy.

The signs at a glance:

• warning light in the instrument cluster on permanently or intermittently
• error message on the display
• diagnostic tool without connection
• fault memory cannot be cleared

If you take these signs seriously, you get clarity about the condition of the system.

Which vehicles is the 9666411980 fitted in?

The control unit 9666411980 is fitted in these vehicles: Citroën C3 II Facelift (2013-2017) and II (2009-2013). Which of them matches your car is shown on the vehicle registration document.

The vehicles at a glance:

• Citroën C3 II Facelift (2013-2017)
• Citroën C3 II (2009-2013)

Compare the part number on the label of the removed unit with this page to confirm that you have the right unit. Have the fault memory read out before removal, because that result shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 00006546T7, 618300400, 626181500, 9656888580, 9673657880, 98 038 323 80.

How does the repair of the 9666411980 work?

Have the fault memory read out and enclose the log. Then disconnect the battery, and only afterwards remove the control unit. Create the repair order online and send the unit in, well packed. At Airbag24 it is checked, defective components are replaced, the stored crash data are erased, and a function test follows.

Processing usually takes 3–4 working days, meaning checking, repairing and testing at Airbag24.

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 9666411980 get to Airbag24?

You can send the unit as a parcel; a UPS collection is available for an extra charge. The repaired unit also comes back via UPS. Put the printed repair order into the parcel and make sure the packaging is shockproof.

A firm casing protects the housing and plugs on the way.