Airbag control unit with part number P31387534

What does the airbag control unit P31387534 do?

The airbag control unit P31387534 is the central control unit of the restraint system (SRS) of Volvo. It evaluates the signals from the crash sensors, decides within milliseconds in an accident which airbags and seatbelt pretensioners to trigger, and reports faults via the airbag warning light.

The device monitors the system constantly and checks the connected components.

After an accident, it stores crash data and locks itself.

Why does the control unit P31387534 fail?

The most common cause is crash data stored after an accident, even without an airbag deployment, which cannot be erased with a normal diagnostic tool. Aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes are also possible causes.

The crash data remain in the unit even if no airbag has deployed. An attempt to erase them with the diagnostic tool is therefore pointless.

The other causes tend to develop gradually: components age, solder joints can go cold, and moisture makes plug connections corrode.

Strong voltage spikes, for example from a weak battery or when starting with an external power source, can also put a strain on the electronics.

How can you tell that the P31387534 is defective?

A defect shows up as the airbag warning light in the instrument cluster, which stays on permanently or intermittently. In addition, there is an error message in the instrument cluster, a lost connection between the diagnostic tool and the control unit, and a fault memory that cannot be cleared.

In an emergency, the airbags and seatbelt pretensioners may then fail to deploy. The warning light makes the defect visible, so its signal must be taken seriously.

Which vehicles is the P31387534 fitted in?

The airbag control unit P31387534 is fitted in these vehicles: Volvo V40 Serie 2 (2012-2016). Whether it suits your own car only becomes clear when you compare it with the list.

The assignment in detail is stored in the overview.

• Volvo V40 Serie 2 (2012-2016)

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

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

How does the repair of the P31387534 work?

First, have the fault memory read out and attach the log. Then disconnect the battery, remove the control unit P31387534 and create a repair order online. Finally, send in the well-packed unit.

This sequence is fixed for safety reasons. The control unit may only be removed after the battery has been disconnected.

Airbag24 checks the unit on the test bench, repairs defective components, deletes the stored crash data and carries out a function test. Testing, repair and test usually take 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 P31387534 get to Airbag24?

You send the control unit P31387534 as a parcel, or book a UPS collection for an extra charge. After the repair, Airbag24 returns your own unit by UPS.

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