Airbag control unit with part number A4519012701

What does the airbag control unit A4519012701 do?

The airbag control unit A4519012701 forms the centre of the restraint system (SRS) in the Smart vehicle. From the readings of the crash sensors it calculates which airbags and seatbelt pretensioners are triggered in an accident, within milliseconds. If it detects a fault, the airbag warning light comes on.

The unit checks the system constantly while you are on the road and logs deviations.

If an accident has occurred, the control unit writes crash data and then locks itself.

Why does the control unit A4519012701 fail?

The most common cause is crash data stored after an accident, even if no airbag has been triggered. An ordinary diagnostic tool cannot delete this data. Other possible causes are ageing electronic components, cold solder joints, moisture and corrosion on plug connectors, and voltage spikes, for example from a weak battery or jump-starting.

The crash data remain stored even though nothing was triggered, so a normal deletion does not help.

At Airbag24 the crash data is deleted during the repair, and the other causes are checked and repaired where necessary.

How can you tell that the A4519012701 is defective?

A defect first shows itself through the airbag warning light in the instrument cluster, which stays on permanently or only intermittently. In addition there are error messages in the instrument cluster, no connection between the diagnostic tool and the control unit, and a fault memory that cannot be cleared. In this state, airbags and seatbelt pretensioners may not deploy in an emergency.

Do not ignore the warning light.

Even if the light goes out again, an entry may remain in the memory.

Which vehicles is the A4519012701 fitted in?

The unit A4519012701 is fitted in these vehicles: Smart Fortwo C451 (2007-2015).

The vehicles are listed below.

• Smart Fortwo C451 (2007-2015)

Check the part number on the label of the unit against this page; then you know it is the right unit, and that comparison says nothing more. Have the fault memory read out in advance. Only this finding shows whether the control unit is defective or whether a plug or cable is causing the fault.

For the same vehicles, we also repair control units with the part numbers A451 820 24 85, A4518201585/001, A4518202285, A4518202485/002, A4519011300Q02.

How does the repair of the A4519012701 work?

Have the fault memory read out and enclose the log, then disconnect the battery and only then remove the control unit. Then create a repair order online and send the unit in well packed. Airbag24 checks it on the test bench, repairs defective components, deletes the crash data and carries out a function test; processing there usually takes 3–4 working days.

The log belongs in the consignment, and the repair order is created before dispatch.

After the function test your unit is returned. 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 A4519012701 get to Airbag24?

You send the control unit A4519012701 as a parcel or book a UPS collection for an extra charge. Airbag24 returns it to you by UPS after the repair.

The printed repair order goes in the parcel; you pack the unit shock-proof.