Description
Airbag Control Unit For Citroën C4. We Do Not Know The Exact Condition Of The Unit; It Is Declared Fully Functional, But Crash Data May Need To Be Erased.
This original equipment airbag control module (SRS ECU) is a direct-fit replacement for vehicles equipped with the Citroën C4 airbag system. Designed to manage deployment logic, monitor crash sensors and store event data, the unit restores proper SRS functionality when the original module is damaged or shows fault codes. Ideal for professional workshops and experienced DIY mechanics searching by part number (9662643980 / 603 72 61 00), this module helps return the restraint system to safe, working order when handled and installed correctly.
Technical Information
- Manufacturer: Stellantis / Citroën
- Model: Citroën C4 (1st Generation)
- Product Codes: 9662643980
- Other Numbers: 603 72 61 00
Applications
Commonly used on Citroën C4 first-generation models. The part is often referenced by the product code 9662643980, which is a key search term for technicians and parts buyers.
Function And Symptoms
The Airbag Control Unit (SRS ECU) continuously monitors impact sensors, seat belt buckle switches and crash signals and decides if and when to trigger airbag inflation. When the unit records a collision event or detects internal faults, the airbag warning light will remain illuminated on the dashboard. Symptoms of a failing module include persistent SRS warning lamp, stored crash data, loss of communication with diagnostic tools or intermittent fault codes related to the restraint system.
Most Common Failure Reasons
- Post-collision status: After an impact the module often records crash flags and disables further deployment until data are cleared or the unit is replaced.
- Water Ingress Or Corrosion: Moisture or corrosion on connectors can cause electrical faults and loss of communication.
- Electrical Disturbances: Short circuits, jump-starts or voltage spikes may damage internal electronics.
- Connector Damage Or Mechanical Stress: Improper removal/installation or damaged harnesses can lead to faults.
Replacement And Installation Recommendations
Only perform replacement if you are qualified and follow safety procedures. General replacement steps used by professionals:
- Disconnect The Battery: Always disconnect the negative battery terminal and wait at least 10 minutes (some manufacturers recommend longer) to allow capacitors to discharge before touching the SRS system.
- Locate The Unit: The airbag ECU is typically mounted inside the passenger compartment (under the dashboard, behind the glovebox or under seats depending on model). Verify location on the specific vehicle before removal.
- Handle With Care: Avoid static discharge and do not open or attempt to repair the module. Remove mounting bolts and disconnect connectors gently.
- Install And Secure: Fit the replacement unit, reconnect all connectors firmly and secure mounting hardware to manufacturer torque specifications.
- Diagnostic Check And Clearing Crash Data: After installation, perform diagnostics and clear any crash data or SRS fault codes using an appropriate diagnostic tool compatible with PSA/Stellantis systems (e.g., DiagBox). Final system verification should confirm the SRS warning lamp extinguishes and that no new faults are present.
Advice For Professionals And DIY Mechanics
This module is intended for users familiar with vehicle safety systems. Always follow the vehicle manufacturer’s procedures for SRS work. If crash data are present, the unit may require erasure and system initialization with a compatible diagnostic tool. Incorrect handling or installation can compromise occupant safety—when in doubt, seek a trained technician.
