Description
Airbag Control Unit CITROËN C4 Fully Functional
High-quality replacement Airbag Control Unit (SRS Module) for Citroën C4, suitable for mechanics and experienced DIYers. This used unit is identified by OE numbers 9662643980 and 603726100 and is commonly searched by those codes — include them in your search to find exact matches. The module handles crash detection, airbag and pretensioner deployment logic, and stores event data; replacing a faulty unit restores safety system integrity and clears SRS faults when programmed correctly.
Technical Information
- Manufacturer: Stellantis / Citroën
- Model: Citroën C4 (First Generation)
- Product Codes: 9662643980, 603726100
- Other Numbers: 654635, 654636
Function And Application
The airbag control unit monitors various crash sensors and vehicle parameters to decide if and when to deploy airbags and seatbelt pretensioners. It also logs crash events and triggers the SRS warning lamp when faults are detected. Proper operation is critical for occupant protection; a fault in the unit can disable airbag deployment or cause false warnings.
Compatibility And Fitment
Designed for Citroën C4 (first generation) platforms and cross-referenced with the listed part numbers. Many buyers locate this part by OE number, so ensure the numbers match your vehicle’s recorded module reference before installation. The unit replaces the original SRS module with the matching codes shown above.
Installation Recommendations
- Always disconnect the vehicle battery before starting work and wait at least 10–15 minutes to allow restraint system capacitors to discharge.
- Follow manufacturer removal and installation procedures and handle the unit carefully to avoid static damage.
- After fitting, perform a full SRS system scan and clear any stored fault codes with an appropriate diagnostic tool; verify the airbag warning lamp extinguishes and run a final system test.
- Professional installation is recommended if you are not experienced with SRS systems — incorrect installation can compromise safety.
Why This Part Commonly Fails
- Damage From Previous Collision — Units removed after airbag deployment often record crash data and must be replaced or reprogrammed.
- Electrical Issues — Short circuits, power surges, or connector corrosion can damage internal electronics.
- Moisture Ingress — Water or humidity reaching the unit or connectors causes corrosion and intermittent faults.
- Physical Damage — Impact, improper handling, or incorrect removal can impair functionality.
Notes For Mechanics And DIY Enthusiasts
Check connector pins and harness condition during replacement. If the unit was removed following an accident, expect crash data to be stored — a diagnostic session is required to confirm status. Do not install a unit that shows signs of physical damage or contamination. After installation, verify SRS system status with a compatible diagnostic scanner and follow all safety procedures.
