Description
Side impact sensor (crash sensor) for Citroën and Peugeot vehicles.
Designed for reliable detection of lateral collisions, this side impact sensor restores correct function of the vehicle’s side airbag deployment system. Suitable for professional garages and competent DIY mechanics, the sensor is often searched by its part numbers and fits several Citroën and Peugeot models. Install with care following airbag safety procedures; a correct replacement eliminates persistent SRS faults and ensures occupant protection in the event of a side impact.
Technical Information
- Manufacturer: Stellantis / Citroën / Peugeot
- Model: Citroën C4, Citroën C5, Peugeot 307, Peugeot 407
- Product Codes: 9646768980
- Other Numbers: 604288200, 8216NZ, 8216GH
Function
The side impact sensor measures lateral acceleration and impact forces. When the sensor detects a side collision that exceeds the airbag control unit’s threshold, it sends an immediate trigger signal to the airbag ECU to deploy side airbags and activate related safety systems (seatbelt pretensioners, etc.). It is a critical component of the Supplemental Restraint System (SRS).
Signs That Replacement Is Needed
- Illuminated SRS/Airbag warning lamp on the dashboard.
- Stored fault codes related to lateral impact sensors in the airbag ECU.
- Physical damage after a collision or visible corrosion/contamination on the sensor or connector.
- Intermittent faults that disappear when connectors are reseated (indicator of poor contact).
Why The Part Commonly Fails
- Moisture intrusion or corrosion at the connector or sensor housing causing electrical faults.
- Physical damage from side impacts, door or seat damage, or improper handling during repairs.
- Wiring harness chafing or connector pin corrosion leading to open/short circuits.
- Aging electronic components can degrade sensitivity or produce inconsistent signals over long service life.
Installation Recommendations
- Always follow airbag safety procedures: disconnect the negative battery terminal and wait at least 2 minutes before starting work to reduce the risk of accidental deployment.
- Locate the sensor (commonly mounted in the B-pillar, door frame, or seat base depending on model), remove interior trim carefully to access mounting points.
- Unplug the electrical connector by depressing the locking tab; inspect the connector and wiring for corrosion or damage and clean if necessary.
- Remove the fixing screws and fit the new sensor in the exact orientation; incorrect orientation can prevent proper detection.
- Reconnect the connector, secure the sensor fasteners to the manufacturer’s seating position (avoid over-tightening), reassemble trim panels.
- After installation, clear SRS fault codes and verify system readiness with a diagnostic tool capable of handling airbag modules (PSA tools such as DiagBox/Lexia/PP2000 or equivalent SRS diagnostic equipment are recommended).
Replacement Interval and Practical Notes
Side impact sensors do not have a scheduled replacement interval and usually remain serviceable for the vehicle’s life unless subjected to impact, moisture ingress, or electrical faults. Replace the sensor if it is damaged, if fault codes persist after troubleshooting, or following an event where the sensor was impacted. Because the sensor is safety-critical, ensure correct part numbers and secure, corrosion-free electrical connections.
Compatibility & Fitment Notes
This sensor is commonly referenced by the part numbers listed above (9646768980 / 604288200 / 8216NZ / 8216GH). These numbers are frequently used when searching for the correct replacement for compatible Citroën and Peugeot models such as C4, C5, 307 and 407. Always verify the part number against the vehicle’s existing sensor to ensure proper match.
