Airbag control unit with part number 3Q0 959 655 BG

What does the airbag control unit 3Q0 959 655 BG do?

The airbag control unit 3Q0 959 655 BG is the central control unit of the restraint system (SRS) of MAN. It evaluates the signals from the crash sensors, decides within a fraction of a second whether to trigger the airbags and seatbelt pretensioners in an emergency, and monitors the system continuously. After an accident, it stores crash data and locks itself.

While the vehicle is being driven, the unit constantly checks whether the wiring, sensors and output stages are in order. If it detects a deviation, it creates an entry in the fault memory and signals the fault via the airbag warning light in the instrument cluster.

Why does the control unit 3Q0 959 655 BG fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. A normal diagnostic tool cannot erase this data. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

• Ageing electronic components on the circuit board
• Cold solder joints
• Moisture and corrosion on the plugs
• Voltage spikes, for example from a weak battery or a jump start

Whether the electronics themselves are affected only becomes clear after testing. Crash data alone does not prove damage to the unit.

How can you tell that the 3Q0 959 655 BG is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently, an error message appears, the diagnostic tool cannot connect to the control unit 3Q0 959 655 BG, or the fault memory cannot be cleared. In this case, the airbags and seatbelt pretensioners may not trigger in an emergency.

The warning light is the most important signal. Restarting the engine does not switch it off by itself.

If the diagnostic tool cannot establish a connection, the control unit is not necessarily to blame. Plugs, cables or the power supply can also be the cause.

Which vehicles is the 3Q0 959 655 BG fitted in?

The airbag control unit 3Q0 959 655 BG is fitted in these vehicles: MAN TGE SY (from 2017).

The following list shows the vehicles for which this part number is recorded.

• MAN TGE SY (from 2017)

Compare the part number on the label of the removed unit with this page. This way you can make sure it is the right unit. Also have the fault memory read out beforehand, because only the log shows whether the control unit itself is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 3Q0959655CL.

How does the repair of the 3Q0 959 655 BG work?

First, have the fault memory of the 3Q0 959 655 BG read out and enclose the log. Then disconnect the battery and only then remove the control unit. Next, create a repair order online and send the unit in well packed. Airbag24 usually needs 3–4 working days for testing, repairing and checking.

At Airbag24, the unit is examined on the test bench. Defective components are replaced, stored crash data is erased and the control unit is then function-tested. Afterwards, your own, repaired unit is sent 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 3Q0 959 655 BG get to Airbag24?

You send the control unit 3Q0 959 655 BG as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

Put the printed repair order into the parcel and pack the control unit shock-proof.