Airbag control unit with part number 9634564780

What does the airbag control unit 9634564780 do?

The airbag control unit 9634564780 forms the central control unit of the restraint system (SRS) for Citroën. It continuously checks the signals from the crash sensors and, in an accident, decides within milliseconds whether airbags and seatbelt pretensioners are triggered.

The unit detects faults in the system itself and shows them via the airbag warning light in the instrument cluster. This way you learn early about a malfunction.

After an accident, the unit stores crash data and locks itself. The next section explains which causes may lie behind this.

Why does the control unit 9634564780 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Aged components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes can also cause a failure.

Stored crash data is therefore no sign that an airbag has deployed. It arises already in an accident in which the airbags do not trigger.

Aged electronic components can cause faults over time. Cold solder joints, moisture and corrosion on plug connections disrupt the connection, and voltage spikes, for example from a weak battery or a jump start, put a strain on the electronics.

How can you tell that the 9634564780 is defective?

A defect shows up as the airbag warning light in the instrument cluster, which lights up permanently or intermittently, or as a fault message in the instrument cluster. In addition, the diagnostic tool does not find a connection to the control unit, and the fault memory cannot be cleared.

Typical signs at a glance:

• Airbag warning light lights up permanently or intermittently
• Fault message in the instrument cluster
• Diagnostic tool does not find the control unit
• Fault memory cannot be cleared

In an emergency, airbags and seatbelt pretensioners may then fail to deploy. That is why such a finding should be checked promptly.

Which vehicles is the 9634564780 fitted in?

The 9634564780 control unit is fitted in these vehicles: Citroën Saxo I Facelift (1999-2003) and I (1996-1999).

The list shows the vehicles that we have on record for this control unit. Use it to check whether your own vehicle is among them.

• Citroën Saxo I Facelift (1999-2003)
• Citroën Saxo I (1996-1999)

First compare the part number on the label of the removed unit with this page; then you know that it is the right unit. Also have the fault memory read out before removal, because only the log 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 550328400, 550579600, 550740800, 9620873680, 9627557780, 9638588680.

How does the repair of the 9634564780 work?

First, have the fault memory read out and attach the log, then disconnect the battery. Only then remove the control unit and create a repair order online, with which you send it in well packed. Airbag24 tests it on the test bench, repairs defective components, erases crash data and runs a function test.

Processing at Airbag24 usually takes 3–4 working days. After that, the unit is returned to you, and the process is complete.

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 9634564780 get to Airbag24?

You send the control unit 9634564780 to Airbag24 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit by UPS.

Put the printed repair order into the parcel and pack the control unit shock-proof.