Airbag control unit with part number 6978373-01

What does the airbag control unit 6978373-01 do?

As the central control unit of the restraint system (SRS) for BMW, the airbag control unit 6978373-01 evaluates the signals from the crash sensors. In the event of an accident, it decides within milliseconds which airbags and seatbelt pretensioners are triggered. It also monitors the system continuously and indicates faults via the airbag warning light.

While the vehicle is being driven, the unit checks the connected components continuously. It stores any irregularities it finds in the fault memory.

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

Why does the control unit 6978373-01 fail?

Crash data stored after an accident is the most common cause, even if no airbag was triggered. A normal diagnostic tool cannot erase it. Other causes include ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes from a weak battery or jump-starting.

The crash data stays in the control unit until it is cleared. A diagnostic tool of the usual kind is not sufficient for this.

The other causes develop over a long time: the electronics age, solder joints become cold, and moisture attacks plug connections.

How can you tell that the 6978373-01 is defective?

The airbag warning light in the instrument cluster stays on constantly or intermittently, and an error message appears. The diagnostic tool finds no connection to the control unit, or the fault memory cannot be cleared. In an emergency, the airbags and seatbelt pretensioners may possibly fail to trigger.

One of these signs points to the finding, but on its own it does not prove that the control unit itself is affected. A plug or a cable can be behind it too.

Then have the fault memory read out before you take any further steps.

Which vehicles is the 6978373-01 fitted in?

The part number determines the assignment, not the vehicle designation alone. The 6978373-01 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).

You will find the vehicles in this overview:

• 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 so that you can be sure it is the right unit. Before removal, have the fault memory read out, because only this log shows whether the control unit is defective or whether a plug or a 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 6978373-01 work?

First have the fault memory read out, enclose the log and disconnect the battery. Then remove the control unit and create a repair order online. Checking, repairing and testing at Airbag24 usually take 3–4 working days.

Send the unit off well packed. Airbag24 checks it on the test bench, replaces defective components, clears the stored crash data and carries out a function test. Your own unit is then 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 6978373-01 get to Airbag24?

You send the unit as a parcel or, for an extra charge, book a UPS collection. After the repair, Airbag24 sends it back to you by UPS.

Place the printed repair order in the parcel and pack the unit securely against impact.