This suspension control unit (ECU) is designed to manage and regulate the vehicle’s suspension functions, improving ride comfort and stability. It is commonly referenced with OE number 9664385080 and internal codes 5273N1, 5273P4 and 5273N2. The unit is suitable for technicians and DIY mechanics who need a direct replacement part for Citroën and Peugeot models that use these references. Including clear product codes in the listing increases findability for customers searching by part number.

Function And Application

The unit Processes Signals From Ride Height And Speed Sensors And Sends Commands To Suspension Actuators And Valves To Maintain Correct Vehicle Level And Damping Characteristics. It Communicates With Other Vehicle Control Modules To Coordinate Stability Systems. Typical Applications Include Vehicles Equipped With Height-Adaptive Or Electronically Controlled Suspension, Where Precise Control Of Ride Height And Response Is Required.

Technical Information

• Manufacturer: Stellantis / Citroën / Peugeot
• Model: Citroën C4 Picasso (Source Vehicle)
• Product Codes: 9664385080
• Additional Numbers: 5273N1, 5273P4, 5273N2

Replacement And Installation

Replacement of the Suspension Control Unit Should Be Carried Out By A Mechanic Or An Experienced DIYer Comfortable With Vehicle Electronics. Typical Steps:

• Disconnect The Battery Before Starting To Prevent Short Circuits And Protect Electronic Components.
• Locate The Unit According To The Vehicle’s Service Manual — Access May Require Removal Of Interior Trim Or Engine Bay Covers.
• Carefully Unplug Electrical Connectors And Remove Mounting Fasteners. Inspect Connectors And Wiring For Corrosion Or Damage.
• Install The New Unit, Secure Fasteners, Reconnect Plugs And Reconnect The Battery.
• Verify System Operation And Clear Any Fault Codes Using A Compatible Diagnostic Tool. Some Vehicles May Require Initialization Or Adaptation Procedures After Replacement.

Installation Recommendations

• Always Disconnect The Battery Before Removal And Reconnection To Avoid Damaging The Unit.
• Protect Connectors From Moisture And Clean Corroded Contacts Prior To Reinstallation.
• Use Proper Tools And Follow Manufacturer Torque Specifications For Fasteners.
• Perform A Full System Check With A Diagnostic Scanner After Installation To Confirm Correct Operation And To Reset Fault Codes.
• If Uncertain About Coding Or Initialization Steps, Seek Assistance From A Technician With PSA Diagnostic Equipment.

Why This Part Commonly Fails

Common Failure Causes Include Water Ingress And Corrosion Of Electrical Connectors, Electrical Surges Or Short Circuits, Mechanical Damage From Road Debris Or Improper Handling, And Age-Related Wear Of Internal Electronic Components. Fault Symptoms Can Include Incorrect Ride Height, Fault Codes Related To Suspension Sensors Or Actuators, And Intermittent Communication Errors With Other Control Modules.

Notes For Buyers

Search By OE Or Internal Codes (9664385080, 5273N1, 5273P4, 5273N2) To Ensure You Locate The Correct Unit. The Unit Originates From A Citroën C4 Picasso And Is Supplied As Shown In The Listing.

This suspension control unit (ECU) is an essential electronic module that manages vehicle height and damping functions on compatible Citroën and Peugeot models. Supplied with manufacturer reference numbers commonly used in searches (9665811380, 0X080336, 5273N1, 5273P4, 5273N2), this unit is ideal for mechanics and experienced DIYers who need a direct replacement part identified by part code. Installing a correct suspension ECU restores proper ride height control, improves vehicle stability and restores fault-free communication with suspension sensors and actuators.

Function And Benefits

The unit monitors height/level sensors and sends commands to valves, pumps or actuators in electronic height control systems. Typical benefits after replacement include restored automatic leveling, elimination of dashboard suspension faults, improved ride comfort and prevention of further mechanical wear caused by incorrect ride height. Because buyers frequently search by product code, this listing highlights all known codes to help you find the exact match quickly.

How Replacement Is Performed

Replacement is straightforward for trained technicians but requires care with electrical connections and system calibration. Typical replacement steps:

• Park on a level surface, engage the handbrake and disconnect the vehicle battery before starting work.
• Access the unit (commonly located in a wheel arch, under the rear seat or inside a body trim panel depending on model) and remove protective covers and fasteners.
• Carefully unplug all electrical connectors—mark positions if needed—and remove mounting bolts.
• Install the new unit, secure fasteners to manufacturer recommendations, and reconnect the connectors ensuring clean contact surfaces.
• Reconnect the battery and perform diagnostic checks and any required calibration or initialization with a suitable diagnostic tool to clear faults and adapt sensors.

Installation Recommendations

• Always Disconnect The Battery Before Removal To Prevent Damage To The Module.
• Inspect Connectors And Wiring For Corrosion Or Damage And Repair As Necessary Before Fitting The New Unit.
• Use A Manufacturer-Compatible Diagnostic Tool To Clear Fault Codes And Perform Any Required Calibration Or Initialization After Fitting.
• Do Not Expose The Unit To High-Pressure Washers Or Excessive Moisture During Installation.
• If You Are Not Confident With Diagnostics Or Electronic Calibration, Have The Final Setup Performed By A Qualified Technician.

Most Common Causes Of Failure

• Water Ingress And Corrosion Of Connectors Or Internal Electronics Leading To Intermittent Faults.
• Electrical Surges Or Short Circuits From Faulty Wiring Or Aftermarket Equipment.
• Connector Damage From Vibration Or Incorrect Handling During Repairs.
• Age-Related Electronic Component Degradation On High-Mileage Vehicles.
• Faults In Related Sensors Or Actuators That Cause The ECU To Go Into Protection Mode.

Technical Information

• Manufacturer: Stellantis (Citroën / Peugeot)
• Model: Citroën C4 Picasso (source vehicle)
• Product Codes: 9665811380, 0X080336, 5273N1, 5273P4, 5273N2
• Other Numbers: 5273N1, 5273N2, 5273P4, 9665811380

Note For Professionals: This control unit is commonly identified by the product codes listed above. Confirm that the part number on the replacement unit matches the number required for the vehicle before installation. Proper diagnostic calibration after installation ensures the suspension system returns to normal operation and prevents recurring fault codes.