Airbag control unit with part number 65.77-5A1FC44-01

What does the airbag control unit 65.77-5A1FC44-01 do?

The airbag control unit 65.77-5A1FC44-01 forms the central unit of the restraint system (SRS) of BMW. It evaluates the crash sensors, determines in an accident within milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

If it detects a fault, it reports this via the airbag warning light. After an accident it stores crash data and locks itself. The lock is only lifted by the repair.

Why does the control unit 65.77-5A1FC44-01 fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered; a normal diagnostic tool cannot erase it. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, such as those caused by a weak battery or a jump start.

Which of these causes applies to your vehicle only becomes apparent from the fault memory read-out. Only after that can you decide how to proceed.

How can you tell that the 65.77-5A1FC44-01 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently as soon as a fault is present. In addition there is a fault message in the instrument cluster, a diagnostic tool without a connection, and a fault memory that cannot be erased.

In an emergency, airbags and seatbelt pretensioners may fail to trigger if there is a defect. Do not leave a warning light that is permanently or intermittently on without having it checked.

Which vehicles is the 65.77-5A1FC44-01 fitted in?

Check first using the part number whether your vehicle is affected. The airbag control unit 65.77-5A1FC44-01 is fitted in these vehicles: BMW 4 Series G23 Convertible (from 2020).

Here is the list of vehicles for this part number:

• BMW 4 Series G23 Convertible (from 2020)

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

How does the repair of the 65.77-5A1FC44-01 work?

First have the fault memory read out and enclose the log with the unit. Then disconnect the battery and only then remove the control unit.

Next, create a repair order online and send the unit in well packed. At Airbag24 it is checked on the test bench, defective components are replaced, crash data is deleted and a function test is carried out. Processing takes 3–4 working days as a rule, before your own unit is returned.

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 65.77-5A1FC44-01 get to Airbag24?

You can send the unit in as a parcel or book a UPS collection for an extra charge. Airbag24 then sends the repaired unit back by UPS.

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