Description
Side Airbag Control Unit for Peugeot 406
This Side Airbag Control Unit is a direct-fit safety electronics module used on Peugeot 406 vehicles. It monitors side impact sensors and controls deployment of side airbags and associated restraint systems. Commonly referenced by the part numbers 9631847080, 550540400 and 8216N0, this unit is intended for professional mechanics and experienced DIYers who service Citroën/Peugeot vehicles. Clear, reliable airbag control is essential after an impact or when airbag system faults are present; replacing the control unit restores correct SRS behavior when the cause of the fault is identified.
Technical Information
- Manufacturer: Stellantis (Citroën / Peugeot)
- Model: Peugeot 406 (1995–2004) — Saloon, Estate, Coupe
- Product Codes: 9631847080, 550540400, 8216N0
- Additional Numbers: 550540400 | 8216N0 | 9631847080
Function And Application
The airbag control unit (SRS ECU) continuously evaluates inputs from side impact sensors and decides whether to trigger the side airbags and pretensioners. It also stores crash data and fault codes used by diagnostic tools. This unit is a critical component of the occupant restraint system on the Peugeot 406 and must be installed and handled following safety precautions.
Fitment And Compatibility
Designed for Peugeot 406 model range produced between 1995 and 2004 (including saloon, estate and coupe variants). Compatibility is typically identified by the OE/product codes printed on the unit: 9631847080, 550540400, 8216N0. Check these numbers on the existing unit during replacement.
Installation Recommendations
- Always disconnect the negative battery terminal before starting work and wait at least 10 minutes to allow the SRS system capacitors to discharge.
- Locate the control unit (position varies by build: commonly under the center console, beneath a seat, or behind interior panels). Remove interior trim panels carefully to access the ECU.
- Document connector positions and locking tabs, then unplug connectors and remove mounting bolts. Avoid pulling on wiring; release locking clips before disconnecting.
- Install the replacement unit in the reverse order. Secure connectors fully and torque mounting bolts to manufacturer specification if available.
- After installation, reconnect the battery and use a suitable diagnostic tool to read and clear SRS fault codes and to confirm system readiness. If faults persist, inspect sensors, wiring and connectors for damage or corrosion.
- Observe electrostatic discharge precautions and do not attempt repairs on airbag module circuits unless qualified.
Why This Part Most Commonly Fails
- Crash Deployment: Units are often replaced after a collision that triggered airbag deployment.
- Water Ingress And Corrosion: Moisture exposure or damaged seals can cause electrical shorts or connector corrosion.
- Electrical Faults: Short circuits, wiring damage or failed connectors can corrupt unit operation.
- Internal Component Degradation: Age, vibration and thermal stress can lead to failed solder joints or electronic components.
- Software Or Stored Faults: Persistent error codes may render the ECU unable to enable the SRS until cleared or the unit replaced.
For workshops and competent DIYers, replacing the Side Airbag Control Unit with a correctly coded and matching part number is the standard procedure to restore safe airbag system operation after a crash or when irreparable SRS faults are present. Using the original product codes listed above helps ensure correct fit and function for Peugeot 406 vehicles.
