Airbag control unit with part number 3C0 909 605 G

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

The airbag control unit 3C0 909 605 G processes the signals from the crash sensors at Volkswagen and triggers the matching airbags and seatbelt pretensioners in an accident, within milliseconds. It is the central unit of the restraint system (SRS).

During operation it monitors the connected components continuously. Faults are made visible via the airbag warning light in the instrument cluster.

After an accident it stores crash data and locks itself.

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

Stored crash data after an accident is the most common cause for the control unit 3C0 909 605 G, even if no airbag has deployed. A standard diagnostic tool cannot delete this data; in addition, aged components, cold solder joints, moisture and corrosion, and voltage spikes play a role.

That no airbag has deployed does not mean there is no crash data. A reading alone therefore does not help.

The other causes develop over time. Components age, solder joints can go cold, and moisture attacks the contacts. Voltage spikes occur, for example, with a weak battery or a jump start.

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

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

The signs at a glance:

• The airbag warning light stays on or keeps coming on.
• An error message appears in the instrument cluster.
• The diagnostic tool finds no connection to the control unit.
• The fault memory cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then not trigger. A finding like this therefore belongs in an inspection.

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

The control unit 3C0 909 605 G is fitted in these vehicles: Volkswagen Passat B6 3C (2005-2010). You can clarify which entry applies to your car by means of the part number on the unit.

The vehicles in detail:

• Volkswagen Passat B6 3C (2005-2010)

Comparing the part number on the removed unit with this page only shows that it is the correct unit. Have the fault memory read out beforehand, as only this shows whether the control unit is defective or a connector or cable is behind it.

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 G work?

First read out the fault memory and enclose the log. Then disconnect the battery, and only after that remove the control unit 3C0 909 605 G. Inspection, repair and function test at Airbag24 usually take 3–4 working days.

Then you create the repair order online and pack the unit well. Airbag24 inspects it on the test bench, repairs defective components, deletes the stored crash data and carries out a function test. Your own unit is returned to you afterwards.

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 G get to Airbag24?

You send the control unit 3C0 909 605 G as a parcel, or book a UPS collection for an extra charge. Airbag24 sends it back to you by UPS after the repair.

Enclose the printed repair order and pack the unit shock-proof.