Airbag control unit with part number 9665495780

What does the airbag control unit 9665495780 do?

The airbag control unit 9665495780 is the central control unit of the restraint system (SRS) for Citroën. It evaluates the signals from the crash sensors and decides within milliseconds which airbags and seatbelt pretensioners are triggered.

The unit monitors the entire system continuously. It shows faults via the airbag warning light in the instrument cluster and stores them in the fault memory.

After an accident the control unit stores crash data and locks itself. It is thus both trigger and data store of the system.

Why does the control unit 9665495780 fail?

The most frequent cause is crash data stored after an accident, even if no airbag fired; a normal diagnostic tool cannot erase it. Further causes are aged electronic components, cold solder joints, moisture and corrosion, and voltage spikes.

The following causes are considered in detail:

• Electronic components wear out over time.
• Cold solder joints can interrupt contacts.
• Moisture and corrosion on plug connectors disturb signal transmission.
• Voltage spikes, for example from a weak battery or a jump start, stress the electronics.

Crash data is the most frequent cause, but a defect can also occur without it. Which cause is present only the test on the test bench shows.

How can you tell that the 9665495780 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which stays on permanently or intermittently, through an error message in the instrument cluster, through a missing connection to the diagnostic tool, and through a fault memory that cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then not trigger.

The signs in detail:

• The airbag warning light stays on permanently or only occasionally comes on.
• The instrument cluster displays a fault message about the airbag system.
• The diagnostic tool does not establish a connection to the control unit.
• A stored fault cannot be cleared from the fault memory.

If any of these signs occurs, have the fault memory read out before you change anything in the system.

Which vehicles is the 9665495780 fitted in?

The control unit 9665495780 is fitted in these vehicles: Citroën C5 II 1st Facelift (2010-2012), II (2008-2010) and II 2nd Facelift (2012-2017).

The following vehicles belong to this part number:

• Citroën C5 II 1st Facelift (2010-2012)
• Citroën C5 II (2008-2010)
• Citroën C5 II 2nd Facelift (2012-2017)

Compare the part number on the label of the removed unit with this page. That only ensures it is the right unit and says nothing about its condition. Also have the fault memory read out before removal. Only this log shows whether the control unit is defective or whether a plug or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers 9657456680, 9665266080, 9665558180, 9674290580.

How does the repair of the 9665495780 work?

First have the fault memory read out and attach the log, then disconnect the battery and remove the control unit. Then create a repair order online and send the unit in well packed. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the control unit on the test bench and carries out repairs on defective components. Afterwards Airbag24 erases the stored crash data and performs a function test. Only then does your own unit go back to you.

The order at the start serves safety: the control unit is removed only once the battery is disconnected. 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 9665495780 get to Airbag24?

You send the unit 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 into the parcel and pack the unit shockproof.