Citroën C3 Aircross III airbag control unit repair

What is a Citroën C3 Aircross III airbag control unit?

The airbag control unit is the central control unit of the restraint system (SRS) in the Citroën C3 Aircross III. It evaluates the signals from the crash sensors and, in an accident, decides within milliseconds which airbags and seatbelt pretensioners deploy. It also monitors the system continuously and reports faults via the airbag warning light.

The control unit is fitted in the Citroën C3 Aircross III (since 2024). It works in the background and usually only draws attention when the airbag warning light comes on. After an accident it stores crash data and locks itself.

If the warning light comes on, having the unit checked is the sensible next step.

Why is the Citroën C3 Aircross III airbag control unit defective?

The most common cause is crash data stored after an accident, even if no airbag deployed; a normal diagnostic tool cannot clear it. Ageing electronic components, cold solder joints, moisture at connectors and voltage spikes may also be the cause.

Other causes are ageing electronic components, cold solder joints, moisture and corrosion at connectors, and voltage spikes, for example from a weak battery or jump-starting. Such damage usually develops gradually and only shows once the control unit fails its self-test.

Typical signs are a permanently lit airbag warning light, a fault memory that cannot be cleared, or a diagnostic tool that cannot connect to the control unit. Do not ignore the warning light, because with a fault the deployment of the airbags is not ensured in an emergency.

Common error codes for Citroën C3 Aircross III airbag control unit repair

You read fault codes from the fault memory with a diagnostic tool. In the Citroën C3 Aircross III they indicate internal faults of the control unit, communication disruptions, supply voltage problems and faults in the airbag firing circuits.

Once you have read out the fault memory, the following list helps you classify the result. It shows codes that can occur with this control unit, and their meaning.

• F620 → Internal control unit fault, not further specified
• F633 → Internal fault in the passenger airbag firing system
• F00F → Control unit no longer transmits on the CAN network
• E650 → Control unit supply voltage too high
• B0001 → Driver airbag firing circuit: resistance too high
• B0028 11 → Front right side airbag: wiring fault, short circuit to ground
• C601 → Open circuit in the driver airbag firing circuit

A code alone does not reliably show that the control unit is defective, because connectors, wiring or an airbag module can also be the cause. Only the check clarifies where the fault lies.

What part numbers are available for the Citroën C3 Aircross III airbag control unit repair?

The part number is on the label of the airbag control unit and determines its exact version. Within the Citroën C3 Aircross III model series there are different numbers depending on equipment and year of manufacture.

We do not yet have any part numbers for this vehicle. Read the number from the label on your unit and enter it in the repair order. It only ensures that it is the right unit; whether it is defective is shown only by reading out the fault memory or by the check.

Here is how to get your repair done: Have the fault memory read out, disconnect the battery and remove the control unit. Then create a repair order online and send in the unit. Processing at Airbag24, with checking, repairing and testing, usually takes 3–4 working days. 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.