Airbag control unit with part number A3C00184105

What is the function of the airbag control unit A3C00184105?

The Bosch airbag control unit A3C00184105 is the central control module for passive safety in the BMW M3 G8x series. It processes sensor data to precisely deploy airbags and seatbelt pretensioners in the event of a crash. This control unit is also known by part numbers 5A19AB7, 65775A19AB7, and under the designation ACSM5.

As the heart of the restraint system, the ACSM5 (Advanced Crash Safety Module 5) continuously evaluates signals from acceleration and pressure sensors throughout the vehicle. It is essential for overall vehicle safety.

When the system detects a collision, it sends ignition commands to the relevant airbags and seatbelt pretensioners within milliseconds, providing optimal protection for occupants. Without a properly functioning control unit, passive safety is severely compromised.

Why does the A3C00184105 control unit fail?

The most common cause of failure for the A3C00184105 control unit is the storage of crash data after an accident, even if no airbags were deployed. Other causes include internal electronic faults that are logged in the fault memory as “Internal Error” and can prevent communication with the device.

Following a collision—even minor rear-end impacts without airbag deployment—the control unit locks itself internally by writing “crash data” into its memory. This condition prevents further operation and requires professional repair to erase the data and reset the unit.

A further typical defect is an internal hardware failure on the circuit board. This often results in complete loss of communication, leaving diagnostic tools unable to access the control unit and causing the airbag warning light to remain steadily illuminated.

How do you recognize a fault in the A3C00184105?

A defective A3C00184105 control unit primarily manifests as a permanently lit or flickering airbag warning light on the instrument cluster. Often, communication via the diagnostic interface is also lost, and the fault memory displays an “Internal Error” or a fault related to the seatbelt pretensioners.

The clearest indication of a malfunction is the airbag warning light that fails to extinguish after the engine starts. This signals a critical error in the safety system that must be promptly inspected at a specialized workshop.

If a workshop’s diagnostic tool cannot establish communication with the airbag control unit, this strongly suggests an internal fault. Similarly, the recording of errors related to seatbelt pretensioners—even after only a minor rear-end impact—is a typical symptom of stored crash data.

In which vehicles is A3C00184105 installed?

The A3C00184105 airbag control unit is primarily found in the sporty BMW M3 G8x series starting from model year 2020. This includes the sedan (G80), the Touring wagon (G81), as well as the Coupe (G82) and the Convertible (G83). At Airbag24, we offer repairs for all these models.

At Airbag24, we repair the A3C00184105 control unit for the following BMW G8x models:

- BMW M3 Sedan (G80) from 2020 onward

- BMW M3 Touring (G81) from 2022 onward

- BMW M4 Coupe (G82) from 2021 onward

- BMW M4 Convertible (G83) from 2021 onward

How does the repair of the A3C00184105 proceed at Airbag24?

After sending your defective A3C00184105 control unit to Airbag24, a professional inspection will be carried out. You will receive a non-binding repair quote. Upon your approval, crash data will be erased, faulty components replaced, and the unit thoroughly tested for functionality. The repair comes with 2 years' statutory liability for defects.

Since control units are safety-critical and expensive components, before removal at a specialized workshop, ensure that the fault truly originates from the control unit itself and not from a sensor or wiring harness.

Upon receipt at Airbag24, technicians analyze the unit to determine the exact cause of the fault. Depending on the issue, repairs may involve erasing crash data, fixing electronic circuits, or replacing defective components on the circuit board.

Repairs only commence after you approve the quote. With over 20 years of experience and more than 20,000 repairs completed, we guarantee expert restoration. Each repair is backed by 2 years' statutory liability for defects.