Airbag control unit with part number 446064205

What is the function of Airbag Control Unit 446064205?

The airbag control unit with part number 446064205, also known as A0004460642 or 0004460642, is the central control unit for the occupant safety system (SRS) in the Mercedes-Benz Vito of the W638 series. It continuously monitors all connected crash sensors, airbags, and seatbelt pretensioners, ensuring their precise activation in the event of a collision.

The device’s primary task is to process sensor signals. It analyzes data from acceleration sensors to assess the severity of an impact and determine which restraint systems need to be activated.

These include front and side airbags, as well as pyrotechnic seatbelt pretensioners. Proper functionality is critical for passenger safety, which is why the system alerts you to internal faults via the airbag warning light.

Why does Control Unit 446064205 fail?

Typical failures of Control Unit 446064205 are often due to internal hardware defects. Common causes include moisture damage from water ingress leading to corrosion on the circuit board, as well as failure of individual electronic components such as voltage regulators, microcontrollers, or memory chips (EEPROM/Flash).

A frequent source of failure is the breakdown of SMD components or MOSFETs responsible for driving ignition circuits. Additionally, open circuits on the PCB caused by aging or vibrations can result in malfunctions.

External factors like improper repair attempts or overvoltage in the vehicle’s electrical system can also cause irreparable damage to sensitive electronic components. Therefore, visually inspecting the removed unit for corrosion or burn marks is an essential first diagnostic step.

It is crucial to carefully verify the part number printed on the housing, as different hardware and software variants exist for the W638. The numbers 446064205, 0004460642, and A0004460642 refer to the same component.

How do you recognize a defect in Control Unit 446064205?

A defective Airbag Control Unit 446064205 typically manifests as a permanently illuminated airbag warning light (SRS light) in the instrument cluster. Often, communication with the control unit via a diagnostic tool becomes impossible, or internal, non‑erasable fault codes remain stored.

Specific fault codes indicating a defect include messages about an “internal control unit error” or errors related to side or crash sensors—even when those sensors are functioning properly.

In some cases, these faults appear even without a prior accident, suggesting an age‑related or environmentally induced hardware failure within the unit.

In which vehicles is Control Unit 446064205 installed?

The airbag control unit with part number 446064205 and its equivalent numbers A0004460642 and 0004460642 is specifically designed for the Mercedes-Benz Vito and V-Class of the W638 series. Airbag24 offers professional repair services for this control unit, which was used in models from 1996 to 2003.

At Airbag24, we repair this control unit for the following model:

Mercedes-Benz: Vito / V-Class (W638 series, model years 1996–2003)

How is Control Unit 446064205 professionally repaired?

Repair of Control Unit 446064205 at Airbag24 begins with an initial inspection based on the provided fault memory log. Defective components—such as microcontrollers, voltage regulators, or memory chips—are then replaced at the circuit board level. Following restoration, a functional test is conducted on a test bench to verify proper operation.

Before removal, the fault memory should be read out and the log attached to the unit. This allows technicians to perform targeted and efficient diagnostics of reported faults.

During repair, damaged SMD components, fuses, or MOSFETs are carefully desoldered and replaced with new parts. Corrupted memory areas in EEPROM or Flash memory are restored with original data whenever possible.

Upon completion of hardware repairs, the unit undergoes testing on a specialized test bench that simulates vehicle sensor signals. We provide 2 years' statutory liability for defects on all repairs performed.