Airbag control unit with part number 31691275500B

What does the airbag control unit 31691275500B do?

The airbag control unit 31691275500B controls the restraint system (SRS) of BMW. It evaluates the signals from the crash sensors and decides in the event of an accident which airbags and seatbelt pretensioners are triggered.

That decision is made within milliseconds. The unit continuously monitors the entire system while doing so.

If it detects a fault, it reports this via the airbag warning light. After an accident, it stores crash data and locks itself.

Why does the control unit 31691275500B fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. Other causes, which also affect the unit in everyday use, are listed below.

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

Other causes in detail:

• aged electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery or jump-starting

How can you tell that the 31691275500B is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently. Other signs include a fault message in the instrument cluster, no connection to the diagnostic tool, and a fault memory that cannot be cleared.

The airbag warning light indicates the fault and should not be ignored. If it lights up permanently or intermittently, have the system checked promptly.

If the diagnostic tool remains without connection or the fault memory cannot be cleared, there is a malfunction. In an emergency, airbags and seatbelt pretensioners may then fail to deploy.

Which vehicles is the 31691275500B fitted in?

The airbag control unit 31691275500B is fitted in these vehicles: BMW 3 Series E46 (1998-2007). The list below names the vehicles individually.

The vehicles at a glance:

• BMW 3 Series E46 (1998-2007)

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 before removal, because only this result 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 285001368, 285001458, 285001681, 31693323800A, 6577-6905491, 6577-6912755.

How does the repair of the 31691275500B 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-packaged unit.

Airbag24 tests the unit on the test bench, replaces defective components, erases stored crash data and carries out a functional test. Processing at Airbag24 usually takes 3–4 working days.

Your own unit is then 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 31691275500B get to Airbag24?

You send the unit 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 unit shockproof.