This activated airbag (SRS) control unit is a direct-fit replacement for Citroën C5 II vehicles and is commonly searched for by its OEM numbers. It’s suitable for professional workshops and experienced DIY mechanics who require a reliable unit to restore the vehicle’s restraint system after an incident or when diagnosing SRS faults. Including the OEM part numbers in the listing increases findability in search engines and helps you match the unit to the vehicle quickly.

Function And Fitment

The airbag control module (SRS unit) monitors crash sensors and decides when to deploy airbags and seatbelt pretensioners. It stores event and crash data (so-called CRASH data) and fault codes related to the restraint system. After a collision, the module may retain crash data that must be cleared or reinitialized before the vehicle’s SRS warnings are reset. This unit is intended for Citroën C5 II applications; compatibility with other models depends on matching OEM numbers listed below.

Technical Information

• Manufacturer: Stellantis (Citroën / Peugeot)
• Model: Citroën C5 II
• Product Codes: 9657456680
• Additional Numbers: 603481900, 6545V0, 6545V1

Installation Recommendations

• Disconnect the negative battery terminal before starting work and wait the recommended time to allow residual charge to dissipate (typically 10–15 minutes) to avoid accidental deployment.
• Locate the unit according to the vehicle repair manual (common mounting locations include under the centre console or beneath the front seats depending on trim and chassis).
• Handle the module carefully: avoid impact, moisture and electrostatic discharge. Protect connectors and wiring during removal.
• Document connector positions and mounting hardware. Remove securing bolts and electrical connectors cleanly; do not force seized plugs.
• After installation, clear SRS fault codes and, if required, clear CRASH data or reinitialize the module using a suitable diagnostic tool. Verify the SRS system status and perform a post-installation system check.
• For safety-critical systems like airbags, professional installation or validation with a qualified diagnostic device is recommended.

Most Common Failure Reasons

• Crash activation — the most frequent reason the unit is replaced is after an accident when the module records CRASH data.
• Water ingress and corrosion — moisture can damage the electronics or connectors, leading to faults.
• Electrical surges or poor grounding — battery issues, jump-starts or wiring faults can damage the unit.
• Connector damage or wiring harness faults — poor contacts produce intermittent SRS warnings.
• Age-related electronic component degradation — while uncommon, prolonged exposure to harsh environments can cause failures.

Replacement Notes

When fitting this unit, ensure OEM numbers match the vehicle requirements. After physical replacement, use a diagnostic tool to clear crash data and confirm the system shows no active SRS faults. If CRASH data is present, appropriate clearing or reprogramming may be required before the airbags and seatbelt pretensioners will function normally.

This listing includes the most commonly searched part numbers to help you find the correct airbag control unit quickly. Always follow the vehicle manufacturer’s safety procedures when servicing restraint systems.

Overview

This airbag control unit (SRS module) is designed for Citroën C5 II vehicles and is commonly referenced by part numbers 9657456680, 603481900, 6545V0 and 6545V1. The module monitors crash sensors and controls the deployment of airbags and seatbelt pretensioners. It stores crash events and fault codes, and when a fault is present the airbag warning lamp on the instrument cluster will illuminate, indicating that the SRS system requires attention.

Why This Part Matters

A correctly functioning airbag control unit is essential for occupant safety. In the event of a collision, the module evaluates sensor inputs and issues deployment commands within milliseconds. Replacing a faulty or deployed unit restores the vehicle’s ability to protect occupants in a subsequent accident and clears persistent SRS fault indications.

How It Fails

• Deployment After A Collision: The most common reason for replacement is activation during an accident—after deployment the module typically requires replacement or reprogramming.
• Water Ingress And Corrosion: Moisture from leaks (sunroof, door seals) or flooded vehicles can corrode connectors and internal circuitry, causing faults.
• Electrical Damage: Voltage spikes from jump-starts, poor battery connections or short circuits can damage internal electronics.
• Connector Or Wiring Faults: Damaged pins, loose connections or broken wiring to crash sensors and restraints can generate persistent SRS errors.

Replacement And Installation

Replacement of the airbag control unit should follow safe SRS handling procedures. Typical replacement steps used by experienced technicians:

• Disconnect The Vehicle Battery And Wait At Least 10 Minutes To Allow Residual Energy To Discharge.
• Remove Interior Trim Panels To Access The SRS Module (Usually Located Under The Center Console Or Seat Base Depending On Model And Trim).
• Unplug Electrical Connectors Carefully, Noting Locking Tabs And Pin Orientation.
• Remove Mounting Fasteners And Extract The Module.
• Install The New Module, Reconnect All Connectors Securely And Refit Trim.
• Perform Post‑Installation Checks With An SRS‑Capable Diagnostic Tool: Clear Fault Codes, Verify Sensor Status And Ensure The Airbag Warning Lamp Extinguishes After Initialization.

Recommendations For Installation

• Use An SRS‑Capable Diagnostic Tool To Read And Clear Faults And To Verify System Integrity After Installation.
• Observe Electrostatic Discharge Precautions And Handle The Unit By Its Housing—Avoid Touching Contacts Directly.
• Always Disconnect The Battery Before Starting Work And Follow The Manufacturer’s Safety Procedures To Prevent Accidental Deployment.
• If The Module Was Replaced Due To A Crash, Inspect All Airbag Components, Seatbelt Pretensioners And Crash Sensors; Replace Any Components That Have Deployed Or Been Damaged.
• Where Required, Have Coding, Initialization Or Sensor Calibration Performed Using An Approved Diagnostic System By A Qualified Technician.

Technical Information

• Manufacturer: Stellantis / Citroën
• Model: Citroën C5 II (Second Generation)
• Product Codes: 9657456680, 603481900, 6545V0, 6545V1
• Additional Numbers: 603481900 | 6545V0 | 6545V1 | 9657456680

Common Symptoms Indicating Module Fault

• Permanent Illumination Of The Airbag Warning Lamp On The Dash.
• Intermittent SRS Warnings Or Stored Crash Data/Memory Errors.
• After A Collision, Airbags Do Not Reset Or System Reports Deployment Status.

Why The Part Is Often Searched By Part Number

Airbag units are frequently identified and ordered by their OEM part numbers (9657456680, 603481900, 6545V0, 6545V1) to ensure correct fitment and compatibility with vehicle wiring and sensor calibration. Searching by these codes increases the chance of matching the exact module variant used in the Citroën C5 II.

Reason For Failure — Summary

In short, SRS modules usually require replacement after activation in a crash, or when damaged by water, corrosion, or electrical faults. Ensuring dry, secure electrical connections and careful handling during repairs reduces the likelihood of premature failure.

Note For Professionals And DIYers

This description is intended for professional mechanics and experienced DIYers familiar with SRS systems. If you are unsure about any step of the replacement, use appropriate diagnostic equipment and safety procedures or consult a qualified technician.