Airbag control unit with part number 46859300

What does the airbag control unit 46859300 do?

The airbag control unit 46859300 controls the restraint system (SRS) in Fiat and Opel. It processes the readings from the crash sensors and, in the event of an accident, determines within milliseconds which airbags and seatbelt pretensioners are triggered. If an accident is followed by a stored event, crash data are saved and the unit locks itself.

During normal driving, the unit continuously checks the system for faults. If a fault is detected, the airbag warning light in the instrument cluster indicates it.

The control unit is therefore both switching point and monitor, because without its evaluation there would be no reliable decision on triggering.

Why does the control unit 46859300 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. A normal diagnostic tool cannot delete this data. Other causes include aged components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

The event is stored in the control unit's memory. The diagnostic tool can read it but cannot remove it.

• Aged electronic components
• Cold solder joints
• Moisture and corrosion at plug connectors
• Voltage spikes, for example from a weak battery or jump-starting

These points are deliberately general, because their effect varies from unit to unit.

How can you tell that the 46859300 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently. In addition, a fault message may appear in the instrument cluster, the diagnostic tool cannot establish a connection to the control unit 46859300, and the fault memory cannot be cleared.

A lit warning light is the system's direct indication and should not be dismissed as trivial.

During a fault, airbags and seatbelt pretensioners may not trigger in an emergency. The fault should therefore be clarified promptly.

Which vehicles is the 46859300 fitted in?

Checking the list is worthwhile before you remove the unit. The control unit 46859300 is fitted in these vehicles: Fiat Ducato 250 2nd Facelift (2014-2024), 250 (2006-2011), 250 3rd Facelift (from 2023) and 250 1st Facelift (2011-2014); Opel Movano C (from 2021).

The list of vehicles follows here:

• Fiat Ducato 250 2nd Facelift (2014-2024)
• Fiat Ducato 250 (2006-2011)
• Opel Movano C (from 2021)
• Fiat Ducato 250 3rd Facelift (from 2023)
• Fiat Ducato 250 1st Facelift (2011-2014)

First compare the part number on the label of the removed unit with this page. This only confirms that it is the correct unit. Additionally have the fault memory read out, because only this result shows whether the control unit itself is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 00046858203, 00046858205, 00046859296, 00046859297, 00046863930, 01356790080.

How does the repair of the 46859300 work?

First have the fault memory read out and attach the log, then disconnect the battery and remove the control unit 46859300. Online, create a repair order before sending in the well-packed unit. Processing at Airbag24 usually takes 3–4 working days.

At Airbag24 the unit is checked on the test bench. Defective components are repaired, the crash data are deleted and a function test is carried out. You then receive 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 46859300 get to Airbag24?

You either send the control unit 46859300 in as a parcel, or you book a UPS collection for an extra charge. Airbag24 returns it after the repair by UPS.

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