Airbag control unit with part number P31334278

What does the airbag control unit P31334278 do?

Within the restraint system (SRS) of Volvo, the airbag control unit P31334278 performs the evaluation. It checks the signals from the crash sensors and decides in an accident within milliseconds which airbags and seatbelt pretensioners are triggered.

The manufacturer number Bosch 0285011089 is also stamped on the housing. The unit monitors the system continuously and reports faults via the airbag warning light.

After an accident it stores crash data and locks itself.

Why does the control unit P31334278 fail?

For the P31334278, the most common cause is crash data stored after an accident, even if no airbag has deployed. Aged components, moisture and corrosion at plug connections, and voltage spikes are also possible.

Crash data cannot be erased with a normal diagnostic tool. At Airbag24 it is erased as part of the repair.

Aged electronic components and cold solder joints are among the technical causes that are hard to narrow down without a check on the test bench.

Moisture and corrosion at plug connections, as well as voltage spikes, for example from a weak battery or a jump start, can also disturb the electronics.

How can you tell that the P31334278 is defective?

A defect in the P31334278 shows first of all as the airbag warning light in the instrument cluster, which lights up permanently or intermittently. In addition, fault messages and connection problems with the diagnostic tool occur.

Pay particular attention to these signs:

• airbag warning light that burns permanently or intermittently
• fault message in the instrument cluster
• diagnostic tool receives no connection to the control unit
• fault memory cannot be cleared

In an emergency, airbags and seatbelt pretensioners may then fail to deploy. Therefore take the warning light seriously.

Which vehicles is the P31334278 fitted in?

With Volvo, this control unit is not fitted in every model, only in certain ones. The P31334278 is fitted in these vehicles: Volvo V70 B Facelift (2013-2016) and B (2007-2013).

The vehicles for this part number are listed here:

• Volvo V70 B Facelift (2013-2016)
• Volvo V70 B (2007-2013)

If the part number on the label of the removed unit matches this page, you have the correct unit. That does not clarify a cause, however: have the fault memory read out beforehand, because it 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 31387019, P31264932, P31406630.

How does the repair of the P31334278 work?

First read out the fault memory of the P31334278 and enclose the log. Then disconnect the battery and remove the control unit before you create a repair order online.

Pack the unit well and send it afterwards.

Airbag24 checks the control unit on the test bench, replaces defective components and carries out a function test. Stored crash data is also erased by Airbag24. Processing usually takes 3–4 working days before your own unit comes back.

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 P31334278 get to Airbag24?

You can send the control unit P31334278 as a parcel, or you 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 unit shock-resistant.