Airbag control unit with part number 3C0 909 605 C

What does the airbag control unit 3C0 909 605 C do?

The airbag control unit 3C0 909 605 C is the central unit of the SRS restraint system on Volkswagen. In an accident it decides which airbags and seatbelt pretensioners are triggered, based on the crash sensors, within milliseconds.

During driving it monitors the entire system. A fault appears on the airbag warning light in the instrument cluster. After an accident the unit stores crash data and locks itself.

These tasks link sensing and triggering in the vehicle.

Why does the control unit 3C0 909 605 C fail?

The most common cause on the 3C0 909 605 C is crash data that was stored after an accident, even without an airbag being triggered. Other possible causes are aged electronics, cold solder joints, moisture and corrosion, as well as voltage spikes.

The crash data remain until someone removes them. A normal diagnostic tool cannot do that. Airbag24 clears the data as part of the repair.

Voltage spikes arise, for example, from a weak battery or when jump-starting.

How can you tell that the 3C0 909 605 C is defective?

The airbag warning light in the instrument cluster lights up on the 3C0 909 605 C, either permanently or intermittently. In addition, an error message appears in the instrument cluster, the diagnostic tool cannot reach the control unit, and the fault memory cannot be cleared.

With such a defect, airbags and seatbelt pretensioners may not trigger in an emergency.

The warning light therefore reports what the system itself has noticed. Anyone who sees it should have the fault memory read out before any parts are removed.

Which vehicles is the 3C0 909 605 C fitted in?

The 3C0 909 605 C is fitted in these vehicles: Volkswagen Passat B6 3C (2005-2010).

The vehicle models are listed here:

• Volkswagen Passat B6 3C (2005-2010)

Compare the part number on the label of the removed unit with this page. This clarifies whether it is the right unit. The fault memory, which you should have read out beforehand, is informative for the cause: it shows whether the control unit is defective or whether a connector or cable is causing the fault.

For the same vehicles, we also repair control units with the part numbers 3C0 909 605 F, 3C0 909 605J, 3C0 909 605M, 3C0909065F, 3C0909605K, 3C0909605N.

How does the repair of the 3C0 909 605 C work?

Processing at Airbag24 usually takes 3–4 working days. For the 3C0 909 605 C, first have the fault memory read out and attach the log, then disconnect the battery and only then remove the control unit. Afterwards, create a repair order online.

The well-packed unit is then sent in. At Airbag24 it is checked on the test bench, defective components are replaced, the crash data is deleted and a function test is carried out. After that, your own unit is returned.

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 3C0 909 605 C get to Airbag24?

You send the control unit 3C0 909 605 C as a package or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

The printed repair order goes into the package, and the unit is packed shock-proof.