Airbag control unit with part number 6N0909603AM

What does the airbag control unit 6N0909603AM do?

The airbag control unit 6N0909603AM takes over control within the restraint system (SRS) of Volkswagen. It reads the crash sensors, decides in an accident within milliseconds whether airbags and seatbelt pretensioners are triggered, and monitors everything continuously. After an accident it stores crash data and locks itself.

Monitoring covers the sensors, the firing circuits and the seatbelt pretensioners. If the unit detects a deviation, it creates an entry in the fault memory and reports the fault via the airbag warning light in the instrument cluster.

Crash data remain in the memory of the control unit, even if the vehicle is then used further.

Why does the control unit 6N0909603AM fail?

Most often the cause is crash data from an earlier accident, even if no airbag was triggered; a normal diagnostic tool cannot erase them. Other causes include ageing electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, for example from a weak battery or a jump-start.

The crash data belong to the memory of the unit and cannot be removed with a conventional diagnostic tool. As a result, the fault persists in the unit.

The other causes concern the electronics themselves. Components age, solder joints can go cold, and moisture or corrosion damage the plug connections. Voltage spikes, for example from a weak battery or a jump-start, put additional strain on the unit.

How can you tell that the 6N0909603AM is defective?

A defect shows up as an airbag warning light that lights up permanently or intermittently, as an error message in the instrument cluster, as a lack of connection between the diagnostic tool and the control unit, or as a fault memory that cannot be erased. In an emergency, the airbags and seatbelt pretensioners may then fail to trigger.

The airbag warning light in the instrument cluster is the clearest warning signal. If it stays on permanently or only comes on now and then, have the system checked promptly.

An error message in the instrument cluster confirms the picture. If there is also no connection to the control unit, that too points to a fault. A fault memory that cannot be erased is another sign.

Which vehicles is the 6N0909603AM fitted in?

The 6N0909603AM is fitted in these vehicles: Volkswagen Polo 3 (6N) (1994-1999) and III 6N2 (1999-2001).

The overview of the models follows here:

• Volkswagen Polo 3 (6N) (1994-1999)
• Volkswagen Polo III 6N2 (1999-2001)

Comparing the part number on the label of the removed unit with this page only shows that it is the right unit. Whether the control unit itself is defective, or whether a plug or cable is the cause, is shown only by the fault memory read out beforehand.

For the same vehicles, we also repair control units with the part numbers 1C0 909 605 A, 1J0 909 603, 6N0 909 601, 6N0 909 603, 6N0909603E, 6Q0 909 601.

How does the repair of the 6N0909603AM work?

Have the fault memory read out and the log enclosed before you disconnect the battery and remove the control unit 6N0909603AM. Next, create a repair order online and send in the well-packed unit. Airbag24 checks it on the test bench, rectifies defects, erases crash data and carries out a function test, after which your own unit goes back.

This sequence is mandatory for safety reasons; removal takes place only after the battery has been disconnected.

Processing at Airbag24 usually takes 3–4 working days. This means the time for checking, repairing and testing in-house.

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 6N0909603AM get to Airbag24?

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

Place the printed repair order in the parcel and pack the unit shock-proof.