Airbag control unit with part number 550404200

What is the function of Airbag Control Unit 550404200?

The airbag control unit with part number 550404200 is the central control module for the occupant protection system, primarily installed in the Peugeot 106. It processes signals from crash sensors to precisely deploy airbags and pretensioners in the event of a collision, ensuring the safety of vehicle occupants.

As the brain of the passive safety system (SRS), this control unit continuously monitors and evaluates data from acceleration sensors. If it detects a collision exceeding predefined thresholds, it sends ignition pulses to the corresponding airbag modules and seatbelt pretensioners within milliseconds.

The device is technically tailored to the Peugeot 106’s vehicle architecture. It is also known under alternative part numbers such as 9623738080, 654779, 261204625, 9630551480, and 550579000—functionally identical and treated equally during repairs. Its internal electronics, which may include modules from manufacturers like Bosch or Delphi, are designed for reliable signal processing.

Why does control unit 550404200 fail?

Failures in control unit 550404200 typically arise from stored crash data after an accident that prevents reactivation, or from internal electronic faults. Common causes include defective components on the circuit board, communication lockouts (e.g., error code 65535), or irreversible locking triggered by the impact.

The most frequent cause of failure is the storage of crash data. After an airbag deployment, the control unit locks itself for safety reasons and must be professionally reset. Simply clearing the fault memory via a diagnostic tool is not sufficient here.

Another common defect is an internal malfunction within the control unit itself. This can manifest through various error codes indicating issues such as excessively high airbag resistance, insufficient supply voltage, CAN bus errors, or overvoltage. Such errors point to faulty electronic components on the printed circuit board.

External factors like water damage or general electrical disturbances in the vehicle’s onboard network can also harm the control unit’s sensitive electronics, leading to total failure. In these cases, component-level repair is required.

How do you recognize a defect in control unit 550404200?

A defect in control unit 550404200 is usually signaled by a permanently illuminated or flashing SRS airbag warning light on the instrument cluster. Additionally, the control unit may become unresponsive during diagnostics, making fault analysis at the workshop impossible and indicating complete failure.

The primary and unmistakable sign is the activated airbag warning light. It does not extinguish after starting the vehicle, alerting the driver that the entire restraint system is disabled and will not function in the event of a crash.

A more serious symptom is a complete loss of communication. When a workshop attempts to read the control unit via the OBD interface, the connection fails. Often, the generic error code 65535 (“control unit defective”) or a similar message appears, suggesting an internal hardware fault.

In any case, these symptoms necessitate immediate inspection at a specialized workshop, as passenger safety is no longer guaranteed. Continuing to drive with the airbag warning light on poses a significant safety risk.

In which vehicles is control unit 550404200 installed?

The airbag control unit 550404200 is specifically designed for the Peugeot 106 and is used across both model phases. At Airbag24, we expertly repair this control unit for both the first series (S1) and second series (S2) of the Peugeot 106, restoring full functionality to the safety system.

Our repair services cover the following specific model variants:

Peugeot 106 S1 (model years 1991–1996)

Peugeot 106 S2 (model years 1996–2003)

How does repair proceed at Airbag24?

At Airbag24, repairing control unit 550404200 follows a certified process. After receiving your unit, our technicians analyze the hardware, fix electronic defects at the component level, and erase persistent crash data. Final functional tests ensure full operational readiness before returning the repaired unit with 2 years' statutory liability for defects.

The process begins after removing the control unit from the vehicle. Please send the defective part securely packaged to our technical center. A preliminary diagnosis at your local workshop helps rule out other potential sources of trouble in the vehicle.

Upon receipt at Airbag24, our specialists conduct a detailed analysis to identify the exact cause of the fault. Subsequently, the stored crash data is professionally erased, and any defective electronic components on the circuit board are replaced with new, high-quality parts.

Following successful repair, each control unit undergoes a comprehensive functional test on a dedicated test bench. Only when all parameters meet the manufacturer’s specifications is the unit approved for return shipment. You will receive a fully functional component backed by 2 years' statutory liability for defects.