Airbag control unit with part number 2Q0 959 655 BL

What does the airbag control unit 2Q0 959 655 BL do?

The airbag control unit 2Q0 959 655 BL is the central control unit of the restraint system (SRS) for Audi. It evaluates crash sensors, decides in a collision within milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

The housing also carries the manufacturer's number Bosch 0285021454.

The unit reports faults via the airbag warning light in the instrument cluster. After an accident, it stores crash data and then locks itself.

Why does the control unit 2Q0 959 655 BL fail?

The most common cause is crash data stored after an accident, even without a triggered airbag; a normal diagnostic tool cannot erase it. Further causes are ageing components, moisture and voltage spikes.

The crash data stays in the memory until Airbag24 erases it as part of the repair. The other causes may arise in the following forms:

• ageing electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery or a jump start

How can you tell that the 2Q0 959 655 BL is defective?

A defect in the 2Q0 959 655 BL shows up as the airbag warning light, which lights up permanently or intermittently. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

Typical signs are:

• Airbag warning light is on permanently or intermittently
• Fault message in the instrument cluster
• Diagnostic tool cannot establish a connection to the control unit
• Fault memory cannot be cleared

The light not being on does not mean the system is in order. A fault message is therefore a reason to have the system checked.

Which vehicles is the 2Q0 959 655 BL fitted in?

The airbag control unit 2Q0 959 655 BL is fitted in these vehicles: Audi A1 GB (from 2018).

Here you can see the vehicles in list form:

• Audi A1 GB (from 2018)

Compare the part number on the label of the removed unit with this page. This only confirms that you have the correct unit. Whether the control unit itself is defective or a plug or cable is the cause is shown only by the fault memory read out beforehand. Have it read out before removal.

For the same vehicles, we also repair control units with the part numbers 2Q0 959 655 AK, 2Q0959655AC.

How does the repair of the 2Q0 959 655 BL work?

First have the fault memory read out and the log enclosed, then disconnect the battery and remove the control unit. Then create a repair order online and send the unit in. Airbag24 tests and repairs it.

The order protects you during removal, because the unit is only released after the battery has been disconnected.

At Airbag24, the unit is checked on the test bench, defective components are repaired or deliberately replaced, crash data is erased and a function test is carried out. 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 2Q0 959 655 BL get to Airbag24?

You send the control unit 2Q0 959 655 BL as a parcel, or you book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

Enclose the printed repair order in the parcel and pack the unit shockproof.