Airbag control unit with part number 3Q0959655AQ

What does the airbag control unit 3Q0959655AQ do?

The airbag control unit 3Q0959655AQ forms the control centre of the restraint system (SRS) in Seat and Skoda. In a crash it evaluates the signals from the crash sensors and decides within milliseconds which airbags and seatbelt pretensioners to trigger. It also monitors the system constantly and shows faults via the airbag warning light.

Monitoring also runs during normal driving. Every irregularity detected is stored in the fault memory so that a workshop can trace it later.

After an accident, the unit creates crash data and locks itself. It is the repair that lifts this lock.

Why does the control unit 3Q0959655AQ fail?

The most common cause: crash data stored after an accident, even if no airbag was triggered; a normal diagnostic tool cannot delete it. Other possible causes include aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, for example from a weak battery or a jump start.

That the airbags stayed silent therefore does not mean that nothing was stored in the unit. The data remains there until it is specifically dealt with.

The other causes develop over a longer period. A connector contact with corrosion shows dropouts first, and a voltage spike in the vehicle electrical system can damage components inside the unit.

How can you tell that the 3Q0959655AQ is defective?

A defect shows up as the airbag warning light in the instrument cluster, which lights up permanently or intermittently. Added to this are an error message in the instrument cluster, a diagnostic tool without a connection to the control unit, or a fault memory that cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then fail to trigger. Please have the warning checked promptly.

The warning light comes from the system itself and indicates the fault directly.

Which vehicles is the 3Q0959655AQ fitted in?

The 3Q0959655AQ is fitted in these vehicles for Seat and Skoda: Seat Leon 3 [5F] (2012-2020); Skoda Octavia 3 [5E] (2012-2017) and 3 [5E] Facelift (2017-2020).

The following overview lists the affected models:

• Seat Leon 3 [5F] (2012-2020)
• Skoda Octavia 3 [5E] (2012-2017)
• Skoda Octavia 3 [5E] Facelift (2017-2020)

(a) Compare the part number on the label of the removed unit with this page. This only ensures that it is the right unit. (b) Have the fault memory read out beforehand. Only this log shows whether the control unit itself or a connector or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers 3Q0 959 655 AA, 3Q0 959 655 AC, 3Q0 959 655 AS, 3Q0 959 655 BH, 3Q0 959 655 CM, 3Q0 959 655 CN.

How does the repair of the 3Q0959655AQ work?

The fault memory is read out first, and you attach the log. Only then do you disconnect the battery and remove the control unit. Finally, you create a repair order online and send in the well-packed unit.

At Airbag24 the unit is examined on the test bench, and defective components are replaced. Airbag24 deletes the stored crash data; a function test follows at the end, and your own unit goes back to you. Processing usually takes 3–4 working days.

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 3Q0959655AQ get to Airbag24?

Your route to Airbag24 is by post: you send the unit in as a parcel, or book a collection by UPS for an extra charge. The return after the repair is also made by UPS.

A printed repair order goes into the parcel. Pack the control unit so that it is shock-resistant.