Airbag control unit with part number 51904690

What does the airbag control unit 51904690 do?

The airbag control unit 51904690 is the control unit of the restraint system (SRS) in the Fiat. It reads the crash sensors and decides in an accident, within fractions of a second, which airbags and seatbelt pretensioners are triggered.

The housing also carries the manufacturer number Bosch 0285011264. The unit monitors the system constantly and indicates faults via the airbag warning light in the instrument cluster.

After an accident it secures the crash data and then locks itself. The function of this unit is decisive for the safety of all occupants.

Why does the control unit 51904690 fail?

The most common cause is crash data that remains in the unit after an accident, even without an airbag having deployed. Aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes such as from a weak battery or jump-starting can also cause the failure.

Crash data cannot be erased with a conventional diagnostic tool. Airbag24 removes it during the repair.

Wear and the environment also play a part. Electronic components age, solder joints can have gone cold, and moisture damages the contacts. Voltage spikes also act on the electronics.

How can you tell that the 51904690 is defective?

A defect in the 51904690 can be recognised by the airbag warning light in the instrument cluster, by a fault message there, and by a fault memory that cannot be cleared. In addition, the diagnostic tool finds no connection to the control unit.

• airbag warning light in the instrument cluster lights up
• fault message in the instrument cluster
• fault memory cannot be cleared
• no connection from the diagnostic tool to the control unit

In this case, the airbags and seatbelt pretensioners may not deploy in an emergency. Take the warning light seriously and have the system checked.

Which vehicles is the 51904690 fitted in?

The 51904690 is fitted in these vehicles: Fiat 500 312 (2007-2024).

The models are listed below.

• Fiat 500 312 (2007-2024)

Comparing the part number on the label of the removed unit with this page only shows whether you have the matching unit. The cause is established by the fault memory, which you should have read out before removal, because it shows whether the control unit itself 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 51782985, 51870005, 51897810, 51918659, 51963734, 519637734.

How does the repair of the 51904690 work?

First have the fault memory read out and enclose the log, then disconnect the battery. Only then remove the control unit, create a repair order online and send the packed unit in last.

At Airbag24 the control unit is checked, defective components are repaired, crash data is erased and a function test is carried out. The unit is then returned to you.

Processing takes 3–4 working days, but this applies only to testing, repair and function testing. 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 51904690 get to Airbag24?

You send the control unit 51904690 as a parcel or book a UPS collection for an extra charge. After the repair you receive the unit back by UPS.

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