Airbag control unit with part number 51816304

What does the airbag control unit 51816304 do?

The airbag control unit 51816304 is the control centre of the restraint system (SRS) in Fiat. It evaluates the crash sensors, decides in a crash on the firing of airbags and seatbelt pretensioners, and monitors the system constantly.

If the unit reports a fault, the airbag warning light in the instrument cluster lights up. After a crash, it stores crash data and locks itself.

In a crash, the evaluation must happen very quickly. That is why the unit's self-check runs permanently.

Why does the control unit 51816304 fail?

Most often these are crash data stored from an accident, even without a triggered airbag; they cannot be erased with a normal diagnostic tool. Further causes are aged components, cold solder joints, moisture and corrosion at plugs, and voltage spikes.

Airbag24 erases the crash data as part of the repair. The remaining causes lie in the electronics themselves or in their connections.

• aged electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes, for example from a jump start or a weak battery

Which cause is present is determined only by testing the unit.

How can you tell that the 51816304 is defective?

A defect is recognised by the airbag warning light in the instrument cluster, which lights up permanently or intermittently, by an error message, by a missing connection to the diagnostic tool, or by a fault memory that cannot be cleared.

• Airbag warning light in the instrument cluster, permanently or intermittently
• Error message in the instrument cluster
• Diagnostic tool receives no connection to the control unit
• Fault memory cannot be cleared

While such a finding exists, the airbags and seatbelt pretensioners may not deploy in an emergency. Therefore have it checked promptly.

Which vehicles is the 51816304 fitted in?

The control unit 51816304 is fitted in these vehicles: Fiat Idea 350 (2004-2005) and 350 Facelift (2005-2008). The part number decides the assignment, not the model name alone.

The list shows the vehicles recorded for this part number.

• Fiat Idea 350 (2004-2005)
• Fiat Idea 350 Facelift (2005-2008)

Comparing the label with this page tells you only about the unit itself, not about the cause of the failure. Whether the control unit is defective or a plug or cable is at fault is shown only by reading out the fault memory. Therefore have it done beforehand.

For the same vehicles, we also repair control units with the part numbers 51716748, 51752040, 51760853, 51816902, 51816903, 51816904.

How does the repair of the 51816304 work?

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

At Airbag24 the unit is examined on the test bench, defective components are replaced, stored crash data is erased and a function test is carried out. Afterwards you get your own unit back.

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 51816304 get to Airbag24?

You send the unit either as a parcel, or you book a UPS collection for an extra charge. The return after repair is by UPS.

Enclose the printed repair order with the unit and make sure it is packed shock-resistant.