Airbag control unit with part number 000 446 02 42 [00]

What is the function of Airbag Control Unit 000 446 02 42?

The control unit with part number 000 446 02 42 is an airbag ECU (ARS/SRS) manufactured by Bosch, serving as the central control unit for the passive safety system in Mercedes-Benz Sprinter models from series W901 to W905. Its primary task is to process sensor data to precisely deploy airbags and seatbelt pretensioners in the event of a crash.

As the “brain” of the occupant protection system, this unit continuously monitors all connected components, including crash sensors, seat occupancy mats, seatbelt pretensioners, and the airbag modules themselves. Upon impact, the control unit determines within milliseconds which restraint systems need to be activated to provide optimal protection for occupants.

Technically, this module is also identified by the designations A0004460242 or the internal Bosch part number 0285001105. It is specifically designed for the vehicle architecture of the Mercedes-Benz Sprinter T1 and communicates via the vehicle’s own data bus with other control units, such as the instrument cluster, to display status information.

What defects occur in 000 446 02 42?

The most common reason for repairing control unit 000 446 02 42 is the storage of crash data after an accident, which results in the unit being locked out. Other typical failures include internal hardware defects that lead to communication issues with diagnostic tools or permanently stored error codes such as “component defective.”

After an impact where airbags or seatbelt pretensioners have deployed, the control unit stores what is known as a “crash record.” This record cannot be erased using standard workshop testers and disables the entire SRS system. The SRS warning light remains illuminated, and the system becomes inoperative.

Another common defect is failure of the internal electronics. This may manifest as a complete loss of communication, rendering the control unit unresponsive via the diagnostic interface. Causes often include defective SMD components, faulty solder joints, failed voltage regulators, or damaged memory chips (EEPROM/Flash) on the circuit board.

External factors such as moisture or peripheral issues can also damage the control unit. Short circuits caused by damaged wiring, faulty connectors, or defective seatbelt pretensioners can result in secondary damage to the main circuit board. Closely related variants, such as part number 000 446 06 42, often exhibit identical fault patterns.

How do you recognize a defect in the airbag control unit?

The clearest symptom of a defect in control unit 000 446 02 42 is the SRS or airbag warning light remaining constantly illuminated in the instrument cluster. Often, the control unit can no longer be read by a diagnostic tool, or non-erasable error codes like “crash data present” are stored.

If the SRS warning light stays on continuously after starting the vehicle, the system indicates a critical fault. In this state, the functionality of airbags and seatbelt pretensioners is no longer guaranteed, posing a significant safety risk.

Another clear sign is when a specialized workshop cannot establish a connection to the airbag control unit using a diagnostic device. The module fails to respond to requests, indicating a severe internal hardware failure.

In addition, specific error messages in the fault memory that cannot be cleared directly point to the control unit. Entries such as “component defective” or “crash data stored” are typical indicators requiring repair of the control unit.

In which vehicles is control unit 000 446 02 42 installed?

The Bosch airbag control unit 000 446 02 42 was specifically developed for the Mercedes-Benz van platform. It is primarily used in the Mercedes-Benz Sprinter T1 generation, covering model series W901, W902, W903, W904, and W905, produced roughly from 1995 to 2006.

At Airbag24, we repair the control unit with part number 000 446 02 42 for the following model:

Mercedes-Benz: Sprinter W905 (model years 1995–2006)

How is control unit 000 446 02 42 professionally repaired?

Professional repair at Airbag24 includes detailed fault analysis, targeted reset of crash data, and electronic restoration down to the component level. After replacing defective parts and thoroughly cleaning the unit, it undergoes a comprehensive functional test to ensure full operational reliability. We offer 2 years' statutory liability for defects on every repair.

Upon submission to Airbag24, the control unit follows a standardized repair process. First comes an initial inspection, during which the fault memory is read and the circuit board is visually examined for corrosion, moisture damage, or burnt components.

Electronic repair follows. For stored crash data, the memory contents are professionally reset using specialized equipment. If a hardware defect is present, faulty components such as resistors, capacitors, voltage regulators, or memory chips (EEPROM) are replaced with new, high-quality parts, and solder joints are reworked.

The final quality check includes a communication test on the test bench and a re‑reading of the fault memory. Only when the unit operates flawlessly and all functions have been restored is it approved for return shipment. In some cases, after reinstallation, it may be necessary to re‑register the control unit in the vehicle or clear faults in other systems.