Airbag control unit with part number 65.77-6946400

What does the airbag control unit 65.77-6946400 do?

The airbag control unit 65.77-6946400 carries out the restraint system (SRS) for BMW. It evaluates the crash sensors, decides in a crash within milliseconds whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After a crash it stores crash data and locks itself.

If the monitoring detects a fault, the unit writes an entry to the fault memory and shows the fault via the airbag warning light.

This way the state of the system remains traceable even without a crash. The unit checks itself in doing so, and that is what distinguishes it from a simple switch.

Why does the control unit 65.77-6946400 fail?

Crash data are the most common cause: the unit stores them after a crash, even when no airbag has deployed, and a standard diagnostic tool does not erase them. Other causes include aged electronic components, cold solder joints, moisture with corrosion at plug connectors, and voltage spikes.

Crash data stay in the memory as a trace of the crash until Airbag24 removes them during the repair. So anyone sending in the unit does not need to have them erased beforehand.

The other causes concern the electronics and their connections, for example when a battery is weak or a jump-start creates voltage spikes.

How can you tell that the 65.77-6946400 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently and thus indicates a defect on the 65.77-6946400. In addition there is an error message in the instrument cluster, no connection from the diagnostic tool to the control unit, and a fault memory that cannot be cleared.

As long as the warning is active, airbags and seatbelt pretensioners may not trigger in an emergency.

Therefore have the finding checked promptly, rather than ignoring the message.

Which vehicles is the 65.77-6946400 fitted in?

The control unit 65.77-6946400 is fitted in these vehicles: BMW 5 Series E61 LCI Touring (2007-2010), E61 Touring (2004-2007), E60 LCI Saloon (2007-2010) and E60 Saloon (2003-2007); BMW M5 E61 Touring (2007-2010).

The overview comes from the data stored for this part number and lists the vehicles recorded there.

• BMW 5 Series E61 LCI Touring (2007-2010)
• BMW M5 E61 Touring (2007-2010)
• BMW 5 Series E61 Touring (2004-2007)
• BMW 5 Series E60 LCI Saloon (2007-2010)
• BMW 5 Series E60 Saloon (2003-2007)

Compare the part number on the label of the removed unit with this page to make sure it is the right unit. Have the fault memory read out before removal, because only this 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 31911421401V, 319145401011, 65 77 9 118 749 01, 65 77 911 4214-01, 65.77 9172018-01, 65.77-6946384.

How does the repair of the 65.77-6946400 work?

First read out the fault memory and enclose the log, disconnect the battery, and only then remove the control unit 65.77-6946400. Then create a repair order online and send in the well-packed unit. At Airbag24, inspection, repair and testing usually take 3–4 working days.

Airbag24 examines the unit on the test bench, replaces defective components and carries out 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 65.77-6946400 get to Airbag24?

You send the control unit 65.77-6946400 as a parcel or arrange a UPS collection for an extra charge. After the repair Airbag24 returns the unit to you by UPS.

Place the printed repair order in the parcel and pack the unit shock-proof.