Description
Airbag control unit for Citroën C4 Picasso. Fully functional.
This SRS airbag control unit (airbag ECU / crash sensor module) is suitable for Citroën C4 Picasso vehicles and is commonly searched by OEM part numbers. Ideal for professional workshops and experienced DIY mechanics who replace safety electronics, the unit helps restore proper airbag system operation after faults that do not involve deployment. Listed product codes make it easy to find exact matches during diagnosis and ordering.
Technical Information
- Manufacturer: Stellantis (Citroën/Peugeot)
- Model: Citroën C4 Picasso
- Product Codes: 9665396680, 9673625180, 610955800
- Additional Numbers: 6546H9, 6546J0, 6546T1
Function and Purpose
The airbag control unit monitors crash sensors and decides when to deploy airbags and pretensioners. It continuously evaluates inputs from impact sensors, seat occupancy sensors and belt tensioners and stores diagnostic trouble codes in case of faults. Proper functioning of the unit is essential for occupant safety and for the correct signalling of SRS warning lamps on the dashboard.
How To Replace
General replacement steps for experienced technicians or competent DIYers:
- Disconnect the negative battery terminal and wait at least 10 minutes to allow SRS capacitors to discharge.
- Remove necessary trim panels to access the unit (location depends on model year; commonly under the dashboard, center console or seat area).
- Carefully unplug all connectors, avoiding stress on wiring and connectors.
- Install the replacement unit, secure mounting points and reconnect connectors.
- Reconnect the battery and perform a full SRS diagnostic scan to read and clear fault codes and to verify system status.
Installation Recommendations
- Always disconnect the battery before any work on the SRS system and follow manufacturer safety procedures.
- Observe electrostatic discharge (ESD) precautions when handling the unit.
- Use a professional diagnostic tool (PSA DiagBox or equivalent) to confirm correct operation after installation and to clear stored codes.
- Make sure connectors are free of corrosion and properly seated; replace damaged terminals or wiring before completion.
Why The Unit Fails
- Crash Deployment: After an impact, the unit often records crash data and frequently requires replacement or specialist reconditioning.
- Water Ingress And Corrosion: Moisture can damage internal electronics or connectors and cause intermittent or permanent failure.
- Electrical Surges Or Short Circuits: Battery issues, jump starts or incorrect wiring can damage the control electronics.
- Connector Damage Or Poor Contact: Vibration and age can lead to poor connections and fault codes.
- Previous Improper Repairs: Non‑professional interventions may leave the module inoperable or with stored faults.
Typical Lifespan
Airbag control units are designed to last the life of the vehicle when undamaged. The most common reasons for replacement are crash events, water damage or electrical faults. Regular inspection of wiring and connectors helps prevent avoidable failures.
