Airbag control unit with part number 985105619R

What is the function of the airbag control unit 985105619R?

The airbag control unit 985105619R is the central control module for the occupant protection system in the Renault Koleos II (model RZG). Manufactured by supplier Autoliv, it processes data from impact sensors and determines whether to deploy airbags and seatbelt pretensioners. Its internal processor, an Infineon XC2336B-40F, stores all system-relevant data, including crash events.

As the brain of the passive safety system, this module continuously monitors all connected sensors and actuators. It analyzes signals from acceleration sensors in real time to assess the severity of a collision and activate the appropriate restraint systems.

The unit is specifically designed for the Renault Koleos II vehicle architecture and communicates with other ECUs via the CAN bus. The use of the dedicated Infineon microcontroller (MCU) is crucial for processing complex deployment algorithms and securely storing operational and fault data.

Why does the control unit 985105619R fail?

A primary cause of failure for the control unit 985105619R is the storage of crash data after an accident, which triggers an internal system lockout. Other common defects include internal electronic faults caused by damaged SMD components, communication failures, or corrosion damage due to moisture ingress. These issues are almost exclusively hardware-related.

After an airbag deployment, crash data is permanently stored in the control unit’s memory—the Infineon XC2336B-40F. This lockout is a manufacturer‑imposed safety feature that prevents reusing a module involved in a crash without proper reset. The unit remains locked even though its hardware is often still intact.

Internal electronic faults are also a frequent cause. Aging, thermal stress, or voltage surges can lead to failures in SMD components such as voltage regulators or communication modules. Cold solder joints or damaged connector contacts can likewise impair functionality, resulting in intermittent or permanent malfunctions.

How do you recognize a defect in the 985105619R?

A defective airbag control unit 985105619R primarily manifests as a constantly illuminated or intermittently flashing airbag warning light on the instrument cluster. Another clear indication is when the control unit becomes unreachable via a diagnostic tool—meaning no communication occurs over the CAN bus. Error codes pointing to an internal ECU fault are also typical.

The most noticeable symptom is the active airbag warning light. It alerts the driver that the restraint system is either non‑functional or only partially operational, posing a significant safety risk.

In the workshop, the defect often shows up as a complete loss of communication. The diagnostic tool cannot establish a connection to the airbag module to read error codes or perform a system check. Stored error codes frequently indicate an “internal fault” or a “communication failure,” directly implicating the control unit itself.

In which vehicles is the 985105619R installed?

The airbag control unit with part number 985105619R is specific to the second-generation Renault Koleos. At Airbag24, we offer professional and reliable repair services for this control unit in the following model.

Renault: Koleos II (model RZG, from year of manufacture 2016 onward)

How is the 985105619R professionally repaired?

At Airbag24, the control unit 985105619R undergoes a standardized inspection and repair process. This includes an initial diagnosis, electronic refurbishment of faulty components, and, if necessary, erasing crash data from memory (crash reset). A final functional test ensures full operability. Each repair comes with 2 years' statutory liability for defects.

Upon submission to Airbag24, an initial inspection is performed first. Communication with the control unit is tested, and the fault memory is read to verify reported symptoms.

The actual repair focuses on the hardware. Defective SMD components are desoldered under ESD‑protected conditions and replaced with new, specification‑compliant parts. If a crash reset is required, crash data is selectively removed from the Infineon XC2336B-40F memory chip using specialized programming tools, without affecting the rest of the software.

Finally, a comprehensive functional test is conducted. All communication channels and responses to simulated signals are checked. Only after a successful test is the control unit approved for return shipment. We provide 2 years' statutory liability for defects on every repair.