Airbag control unit with part number 3Q0959655AK

What does the airbag control unit 3Q0959655AK do?

The airbag control unit 3Q0959655AK performs the evaluation within the restraint system (SRS) of Seat and Skoda. In a crash it decides within milliseconds which airbags and seatbelt pretensioners fire, and the crash sensors provide it with the basis for that decision. During operation it monitors the system and reports faults via the airbag warning light.

After an accident the unit stores crash data and locks itself in this state. This property is a fixed part of the system's design.

Why does the control unit 3Q0959655AK fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. Other causes are aged components, cold solder joints, moisture and corrosion on connectors, and voltage peaks.

Other causes in detail:

• aged electronic components in the unit
• cold solder joints on the circuit board
• moisture and corrosion on plug connections
• voltage peaks, for example from a weak battery or a jump start

The crash data remains in memory. A standard diagnostic tool cannot access this data.

How can you tell that the 3Q0959655AK is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently, an error message is shown in the instrument cluster, the diagnostic tool cannot find the control unit, and the fault memory remains. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

• The airbag warning light stays on or flashes.
• An error message is shown in the instrument cluster.
• The diagnostic tool cannot find the control unit.
• The fault memory cannot be cleared, even after an attempt to clear it.

If you notice these signs, take the vehicle to a workshop promptly, because the warning light already reports the fault.

Which vehicles is the 3Q0959655AK fitted in?

Checking the list is the first step before you send anything in. The airbag control unit 3Q0959655AK is fitted in these vehicles: Seat Leon 3 [5F] (2012-2020); Skoda Octavia 3 [5E] (2012-2017) and 3 [5E] Facelift (2017-2020).

The following vehicles are recorded for this part number:

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

Two checks come before that. Matching the part number on the label of the removed unit only confirms that you have the right unit in front of you. The fault memory, on the other hand, shows whether the control unit is defective or whether a connector or 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 3Q0959655AK work?

The fault memory is read out first, and the log goes into the parcel. Then you disconnect the battery, only then remove the control unit, and create a repair order online. Processing at Airbag24 usually takes 3–4 working days.

At Airbag24 the unit is examined on the test bench, defective components are replaced, stored crash data is erased and a function test is carried out. Then your unit goes back to you.

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 3Q0959655AK get to Airbag24?

You send the unit as a parcel, or arrange a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

The parcel must contain the printed repair order and shock-proof protection for the unit.