Airbag control unit with part number 985107400R

What is the function of the airbag control unit 985107400R?

The airbag control unit 985107400R is the central control module for the passive safety system in certain Renault models. It processes data from crash sensors and is responsible for precisely deploying the airbags and seatbelt pretensioners at the right moment in the event of a collision.

As an original Renault component, this control unit serves as the brain of the entire occupant restraint system. It continuously monitors vehicle dynamics via a network of acceleration and pressure sensors to detect potential collisions early on.

As soon as the sensors register values indicating an impact, the electronics within the 985107400R control unit analyze the data in milliseconds. Based on the severity and nature of the accident, it determines which safety systems—such as front airbags, side airbags, or seatbelt pretensioners—need to be activated to provide optimal protection for occupants.

Why does the 985107400R control unit fail?

The most common reason for requiring repair of the 985107400R control unit is not a conventional technical defect, but rather the storage of crash data after an airbag deployment. This data locks the unit and cannot be cleared using standard workshop diagnostic tools.

Following an accident in which airbags or seatbelt pretensioners have deployed, the control unit writes a permanent fault entry into its internal memory. This so‑called “crash lock” is a manufacturer‑specified safety feature designed to ensure that the entire system undergoes professional inspection after an accident. As a result, the unit becomes locked and displays a persistent error message.

Another, less frequent cause of failure may be an internal malfunction that disrupts or blocks the vehicle’s electronic systems. However, in most cases, a targeted “crash reset” is sufficient to restore full functionality.

This control unit is also known under the alternative OEM number 985100475R. Repairs are offered for both variants, as their technical foundations are identical.

How can you recognize a fault with the 985107400R?

The clearest symptom of a malfunction is the permanently illuminated airbag warning light on the instrument cluster. Additionally, the crash record stored in the fault memory cannot be erased using conventional diagnostic equipment, indicating a locked control unit.

If the airbag warning light remains steadily lit even after restarting the vehicle, this signals a serious issue within the restraint system. Such a vehicle would fail to pass a mandatory technical inspection.

When reading the fault memory at a workshop, typical error codes such as “crash data stored” or “control unit defective” will appear. Attempts to clear these errors prove unsuccessful, as the lock is embedded at the hardware level within the device’s memory.

In which vehicles is the 985107400R control unit installed?

The airbag control unit 985107400R is an original Renault part used across various models and generations of the brand. It is primarily found in the first‑generation Renault Captur, as well as older models like the Latitude, Express, and Master.

At Airbag24, we professionally repair the control unit with part number 985107400R for the following specific Renault models and series:

Renault Captur I (2013–2019)

Renault Latitude I (2010–2015)

Renault Express I (1985–1998)

Renault Master I (1980–1997)

To ensure complete compatibility, it is essential to verify the part number printed on the control unit’s housing before removal and shipment.

How is the 985107400R professionally repaired?

Professional repair focuses on resetting the stored crash data. The unopened original control unit is sent in, where specialists unlock the internal memory lock and restore the device to its pre‑accident fully functional state.

After sending the removed, unopened control unit to Airbag24, the repair process begins. Technicians access the internal memory and carefully erase the permanently stored crash information. This procedure requires specialized equipment and expert knowledge.

Subsequently, the control unit’s software is checked against its original configuration, and the device undergoes a comprehensive functional test. This ensures seamless communication with the vehicle’s electronics and full compliance with all safety‑related functions.

Repairing the original part eliminates the need for re‑coding or reprogramming in the vehicle. Once installed, the control unit is immediately ready for use (plug-and-play). Each repair comes with 2 years' statutory liability for defects.