Airbag control unit with part number 9633504380

What does the airbag control unit 9633504380 do?

The airbag control unit 9633504380 forms the central control unit of the restraint system (SRS) for Citroën. It evaluates the signals from the crash sensors and, in a crash, decides within milliseconds which airbags and seatbelt pretensioners are triggered.

In addition, it checks the function of the system continuously. If a fault is detected, the airbag warning light in the instrument cluster comes on.

After a crash the unit stores crash data and locks itself.

Why does the control unit 9633504380 fail?

Stored crash data after an accident is most often the cause, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other causes are ageing electronic components, cold solder joints, moisture and corrosion on plug connectors, and voltage spikes.

Airbag24 clears the crash data during the repair.

In detail, these further causes may apply:

• ageing electronic components
• cold solder joints
• moisture and corrosion on plug connectors
• voltage spikes, for example from a weak battery or jump-starting

The fault memory will show which of these applies to your vehicle.

How can you tell that the 9633504380 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which stays on permanently or intermittently, through error messages in the instrument cluster, through no connection to the diagnostic tool, and through a fault memory that cannot be cleared. Airbags and seatbelt pretensioners may then fail to deploy in an emergency.

Typical signs:

• airbag warning light stays on permanently or intermittently
• error message in the instrument cluster
• diagnostic tool has no connection to the control unit
• fault memory cannot be cleared

The warning light shows the defect, so take it seriously. Have the system checked promptly.

Which vehicles is the 9633504380 fitted in?

The assignment applies to Citroën. The control unit 9633504380 is fitted in these vehicles: Citroën Xantia II (1998-2001).

The list in detail:

• Citroën Xantia II (1998-2001)

Compare the part number on the label of the removed unit with this page, so that you can confirm it is the correct unit. Also have the fault memory read out before removal. Only this result shows whether the control unit is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 550519300, 550535300, 550740900, 9622585880, 9633621380, 9639015480.

How does the repair of the 9633504380 work?

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

Airbag24 checks the unit on the test bench, renews defective components and clears stored crash data. A function test follows, and your own unit comes 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 9633504380 get to Airbag24?

You send the unit as a parcel, or you book a UPS collection for an extra charge. After the repair Airbag24 sends it back by UPS.

The printed repair order goes in with the parcel, and the unit is packed shock-resistant.