Airbag control unit with part number 65.77-5A19AB9-01

What does the airbag control unit 65.77-5A19AB9-01 do?

The airbag control unit 65.77-5A19AB9-01 coordinates the restraint system (SRS) in BMW. It processes the signals from the crash sensors, selects the airbags and seatbelt pretensioners to be triggered in a crash, and monitors the system continuously.

If a fault is detected, the airbag warning light in the instrument cluster signals the problem. The decision to trigger is made within milliseconds.

After a crash, crash data lands in memory and the unit locks itself.

Why does the control unit 65.77-5A19AB9-01 fail?

Stored crash data is the most common cause, and this applies even when no airbag was triggered in the accident. Beyond that, aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes must be mentioned.

Crash data cannot be erased with an ordinary diagnostic tool. Erasure takes place at Airbag24 as part of the repair.

The other causes can only be named in general terms: electronics age, solder joints can stay cold, wet and rust attack contacts, and voltage spikes arise, for example, from a weak battery or jump-starting.

How can you tell that the 65.77-5A19AB9-01 is defective?

The airbag warning light in the instrument cluster indicates the defect by lighting up permanently or intermittently. In addition, an error message appears in the instrument cluster, the diagnostic tool finds no connection to the control unit, and the fault memory cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

Which vehicles is the 65.77-5A19AB9-01 fitted in?

Several vehicles are stored for this part number. The control unit 65.77-5A19AB9-01 is fitted in these vehicles: BMW 3 Series G20 LCI Saloon (2022-2024), G20 Saloon (2019-2022), G20 LCI Saloon (from 2024), G21 Touring (2019-2022), G21 LCI Touring (2022-2024) and G21 LCI Touring (from 2024).

The list gives the details:

• BMW 3 Series G20 LCI Saloon (2022-2024)
• BMW 3 Series G20 Saloon (2019-2022)
• BMW 3 Series G20 LCI Saloon (from 2024)
• BMW 3 Series G21 Touring (2019-2022)
• BMW 3 Series G21 LCI Touring (2022-2024)
• BMW 3 Series G21 LCI Touring (from 2024)

Compare the part number on the label of the removed unit with this page; that only shows you have the right unit. Have the fault memory read out beforehand, since only this log shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 5B4490501, 65 77 9 873 891, 65.77-9476852-01, 65.77-9873894-01, 65779476850, 65779873892.

How does the repair of the 65.77-5A19AB9-01 work?

First the fault memory is read out, and you attach the log. Then disconnect the battery and only then remove the unit. Afterwards create a repair order online; processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components, erases stored crash data and runs a function test. 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 65.77-5A19AB9-01 get to Airbag24?

Either you send the unit as a parcel, or you have it collected by UPS for an extra charge. After the repair, UPS brings your own unit back to you.

Put the printed repair order in the parcel and pack the control unit shock-resistant.