Airbag control unit with part number P31406631

What does the airbag control unit P31406631 do?

The airbag control unit P31406631 is the central control unit of the restraint system (SRS) in Volvo. It checks the signals of the crash sensors, determines within milliseconds in an emergency which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It shows faults via the airbag warning light; after an accident it stores crash data and locks itself.

The unit performs these tasks in the background, without you noticing anything. Only a fault makes the system visible in everyday use.

Why does the control unit P31406631 fail?

The most common cause is the crash data stored after an accident, even if no airbag has deployed. Other causes include ageing electronic components, moisture or voltage spikes.

Crash data cannot be erased with a normal diagnostic tool. Airbag24 erases it only during the repair.

Other causes in detail include:

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

How can you tell that the P31406631 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently when a fault is present. A fault message may also appear in the instrument cluster, or the diagnostic tool cannot connect to the control unit. A fault memory that cannot be cleared is also a sign of a defect.

In an emergency, airbags and seatbelt pretensioners may then not trigger reliably. Therefore arrange a check as soon as you notice any of these signs.

Which vehicles is the P31406631 fitted in?

The control unit P31406631 is fitted in these vehicles: Volvo V40 Serie 2 (2012-2016). Your vehicle registration document shows whether your car belongs to the models listed.

This is what the list looks like:

• Volvo V40 Serie 2 (2012-2016)

Comparing the part number on the label of the removed unit only confirms that it is the right unit. Having the fault memory read out is the next step, because it shows whether the control unit or a plug or cable is affected.

For the same vehicles, we also repair control units with the part numbers 285001147, 30611294, 30612702D, P31406938, P31429510.

How does the repair of the P31406631 work?

First have the fault memory 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 in the well-packed unit. Processing at Airbag24 usually takes 3–4 working days, because the unit is checked there, components are repaired, crash data is erased and a function test is carried out.

Afterwards your own unit is returned 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 P31406631 get to Airbag24?

You send the unit to Airbag24 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

The printed repair order goes into the parcel, and the unit is packed shock-proof.