Airbag control unit with part number A4519012901

What does the airbag control unit A4519012901 do?

The airbag control unit A4519012901 is the central control unit of the SRS restraint system in Smart vehicles. It checks the crash sensors, decides in an accident whether airbags and seatbelt pretensioners deploy, and continuously monitors itself.

The unit reports faults via the airbag warning light. After an accident it stores crash data and then locks itself.

Why does the control unit A4519012901 fail?

Most often the cause is crash data stored after an accident, even if no airbag has deployed. Other causes are ageing electronics, cold solder joints, moisture on plugs and voltage spikes.

Crash data cannot be erased with a standard diagnostic tool. Airbag24 takes care of the erasure during the repair.

Electronic components can age over time. Solder joints can go cold, and moisture or corrosion can damage plug connections.

Voltage spikes occur, for example, with a weak battery or when jump-starting.

How can you tell that the A4519012901 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently. In addition, an error message appears, the diagnostic tool does not connect to the control unit, and the fault memory cannot be cleared.

These signs indicate a fault in the restraint system.

In an emergency, airbags and seatbelt pretensioners may then fail to deploy, so have the finding checked promptly.

Which vehicles is the A4519012901 fitted in?

The A4519012901 is fitted in these vehicles: Smart Fortwo C451 (2007-2015). Check before removal whether your car is among them.

These vehicles are included:

• Smart Fortwo C451 (2007-2015)

Compare the part number on the label of the removed unit with this page. That only confirms that you have the right unit. Whether the control unit itself is defective, or whether a plug or cable is the cause, is shown only by the fault memory. So have it read out beforehand.

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 A4519012901 work?

Have the fault memory read out first and put the log in the parcel. Then disconnect the battery, remove the control unit and create the repair order online. Processing at Airbag24 usually takes 3–4 working days.

Send the unit off well packed. Airbag24 checks it on the test bench, repairs defective components, erases the crash data and carries out a function test.

Only then is your own unit sent back 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 A4519012901 get to Airbag24?

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

Print the repair order and put it in the parcel. The unit must be packed shockproof.