Airbag control unit with part number 31406938

What does the airbag control unit 31406938 do?

In the vehicle of Volvo, control unit 31406938 takes over control of the restraint system. It evaluates the crash sensors, decides in an accident on the triggering of airbags and seatbelt pretensioners, and monitors the system continuously. It indicates faults via the airbag warning light.

In everyday use the unit works unobtrusively in the background and constantly checks sensors, wiring and trigger electronics. Deviations end up in the fault memory.

After an accident it stores crash data and locks itself. Only the repair lifts this lock.

Why does the control unit 31406938 fail?

Crash data stored after an accident is at the top of the causes, even when no airbag was triggered. Further causes lie in components, plug connections and the power supply of the 31406938.

A normal diagnostic tool cannot erase the crash data. Airbag24 removes it during the repair.

The further causes at a glance:

• aging 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 31406938 is defective?

A defect in the 31406938 shows up as the airbag warning light, which lights up permanently or intermittently, and as a fault message in the instrument cluster. In addition, the diagnostic tool gets no connection to the control unit, or the fault memory cannot be cleared. Airbags and seatbelt pretensioners may then fail to deploy in an emergency.

These signs occur individually or together:

• airbag warning light lights up permanently or intermittently
• fault message in the instrument cluster
• no connection between diagnostic tool and control unit
• fault memory cannot be cleared

If you notice any of these signs, have the system checked promptly before you rely on the restraint systems.

Which vehicles is the 31406938 fitted in?

Control unit 31406938 is installed in these vehicles: Volvo V40 Serie 2 Facelift (2016-2019) and Serie 2 (2012-2016). What counts is what we have recorded for this number.

The vehicles in detail:

• Volvo V40 Serie 2 Facelift (2016-2019)
• Volvo V40 Serie 2 (2012-2016)

Comparing the part number on the label of the removed unit with this page ensures that it is the right unit. Still, have the fault memory read out beforehand, because only this result shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers P31350547, P31387534, P31406254, P31406534, P31406631, P31406938.

How does the repair of the 31406938 work?

For the 31406938, first have the fault memory read out and attach 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. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, repairs defective components, erases stored crash data and runs a functional test. Afterwards your own 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 31406938 get to Airbag24?

You send control unit 31406938 as a parcel or book a UPS collection for an extra charge. Airbag24 sends it back by UPS after the repair.

The printed repair order belongs in the parcel. Pack the unit shockproof so that it arrives protected.