Airbag control unit with part number A9079020303

What is the function of the airbag control unit A9079020303?

The airbag control unit A9079020303 is the central safety module in the Mercedes-Benz Sprinter W907/W910. It processes data from crash sensors and, in the event of an accident, activates vital occupant restraint systems such as airbags and seatbelt pretensioners. Technically, it is often equivalent to the Bosch control unit 0 285 015 024.

As an airbag ECU (Electronic Control Unit) or SRS control unit (Supplemental Restraint System), this module serves as the brain of the passive safety system. It continuously monitors all connected components, from the acceleration sensors at the front and sides of the vehicle to the ignition circuits of individual airbags and seatbelt pretensioners.

Under normal operating conditions, the control unit ensures the system remains ready. If it detects an impact exceeding predefined thresholds, it sends ignition pulses to the corresponding pyrotechnic actuators within milliseconds, providing optimal protection for occupants.

Why does the control unit A9079020303 fail?

The most common cause of failure for the control unit A9079020303 is the storage of crash data after an airbag deployment. This data permanently locks the control unit. Another major cause is internal electronic defects in circuit board components, leading to communication errors or complete loss of functionality.

Following a crash, crash data is irrevocably stored in the control unit’s internal memory (EEPROM/Flash). This lockout is intentionally designed by the manufacturer to prevent reuse of a potentially damaged unit. However, a qualified workshop can safely reset this data during repair ("crash reset").

Even without an accident, electronic components such as voltage regulators, driver ICs for igniters, or capacitors may fail. Cold solder joints or issues with CAN/LIN communication interfaces are also well-known sources of failure requiring repair.

The control unit A9079020303 is listed by Bosch under part number 0285015024. Depending on the vehicle configuration, other part numbers like A9079000304 or A9079017900 may be installed, all sharing a similar technical foundation.

How do you recognize a defective A9079020303 control unit?

A defect in the A9079020303 control unit almost always manifests as a persistently illuminated airbag or SRS warning light on the instrument cluster. Additionally, fault codes stored in the error memory—especially after an accident or due to internal component failures—cannot be permanently cleared using a diagnostic tool.

The illuminated warning light is the clearest indicator, signaling that the entire restraint system is non-functional and may fail to deploy in the event of a crash.

When reading the error memory with a suitable diagnostic device (e.g., Xentry), specific fault codes appear. Common messages include “Control unit internal error” or references to stored crash data, indicating the unit is locked.

In some cases, clear text messages also appear on the vehicle’s display, such as “Airbag system defective” or “Visit SRS workshop,” directly alerting the driver to the issue.

In which vehicles is the airbag control unit A9079020303 installed?

The airbag control unit A9079020303 is specifically designed for the third-generation Mercedes-Benz Sprinter. At Airbag24, we repair this control unit for the W907 and W910 series, produced since around 2018 and delivered as vans, buses, or chassis/cab variants.

The exact assignment of the part number may vary depending on the production period and trim level. The W907 (front-wheel drive) and W910 (rear/all-wheel drive) series covered here span roughly 2018–2021 and beyond, during which this control unit was installed.

It is crucial that the part number of the removed unit exactly matches A9079020303 or the equivalent Bosch number 0285015024 to ensure compatibility and proper functionality after repair.

How does the repair of A9079020303 proceed at Airbag24?

At Airbag24, the submitted A9079020303 control unit undergoes a professional repair process. Following an initial inspection on the test bench, the error memory is read. Depending on the defect, crash data is reset or faulty electronic components on the circuit board are replaced. A final functional test confirms quality.

After careful removal from the vehicle, please send the defective control unit along with a detailed description of the fault to Airbag24. Our technicians perform a precise diagnosis to identify the root cause—whether it’s data locking or a hardware defect.

The core of the repair involves either selectively erasing the crash data from the memory chip or overhauling the electronics at the component level. During this process, all vehicle-specific configurations and calibrations are preserved, ensuring that the control unit is fully functional again immediately after reinstallation—plug-and-play.

Following successful repair and final inspection, the unit will be shipped back to you. We provide 2 years' statutory liability for defects on every repaired unit.