Airbag control unit with part number A4519013301

What does the airbag control unit A4519013301 do?

The airbag control unit A4519013301 is the central control unit of the SRS in the Smart. It evaluates the signals from the crash sensors and, in the event of an accident, determines within milliseconds whether airbags and seatbelt pretensioners are triggered.

The unit monitors the system's components without interruption. A detected fault is shown via the airbag warning light.

After an accident it stores crash data and locks itself. This lock is lifted only by the repair.

Why does the control unit A4519013301 fail?

The most common cause of a failure of the A4519013301 is crash data stored after an accident, even if no airbag has deployed. Ageing electronics, moisture, cold solder joints and voltage spikes can also contribute.

Crash data cannot be erased with a standard diagnostic tool. Airbag24 removes it as part of the repair.

Other possible causes include:

• ageing of the electronic components
• cold solder joints on the circuit board
• moisture and corrosion at plug connections
• voltage spikes from a weak battery or a jump start

How can you tell that the A4519013301 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently when the A4519013301 is defective. An error message usually appears alongside it, the diagnostic tool cannot reach the control unit, and the fault memory cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then fail to deploy even though the vehicle drives normally. The warning must therefore not be ignored.

The light makes the finding visible and calls for a check.

Which vehicles is the A4519013301 fitted in?

The control unit A4519013301 is fitted in these vehicles: Smart Fortwo C451 (2007-2015). This information refers to the part number A4519013301.

The following vehicles belong to this control unit:

• Smart Fortwo C451 (2007-2015)

Carry out the label comparison on the removed unit with this page to confirm you have the right unit. Only the fault memory shows whether the control unit is actually defective or whether a cable or connector is causing the fault, 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 A4519013301 work?

Processing the A4519013301 at Airbag24 usually takes 3–4 working days, and this period covers testing, repairing and checking only.

Before sending, have the fault memory read out and enclose the log. Then disconnect the battery and remove the unit. Create a repair order online, then pack the control unit carefully.

Airbag24 tests it on the test bench, replaces defective components, erases the stored crash data and carries out a function test. 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 A4519013301 get to Airbag24?

The control unit A4519013301 reaches Airbag24 either as a parcel or via a UPS collection for an extra charge. After the repair, UPS returns it.

The parcel contains the printed repair order, and the unit is packed shock-proof.