Description
AFIL lane departure sensor number 4 for Citroën and Peugeot vehicles. The screw that holds the unit to the wheel arch may be seized or sheared off — it may need to be drilled out.
This AFIL (Lane Departure Warning) sensor is an OEM-style replacement part designed for Stellantis group vehicles, helping the vehicle detect lane markings and support driver-assist systems. Ideal for professional workshops and experienced DIYers, the unit is often searched by its part numbers — fitment and quick identification via the product codes below speed up diagnosis and repair.
How It Works
The AFIL sensor monitors lane markings and vehicle position relative to lane lines to trigger warnings or assist systems when the vehicle unintentionally drifts. It communicates with the vehicle’s driver assistance systems and requires correct electrical connection and, in many cases, calibration via diagnostic equipment after installation to ensure proper operation.
Typical Symptoms And When To Replace
Common signs that the AFIL sensor requires replacement include persistent lane-assist warnings on the dashboard, intermittent or no lane detection, and fault codes related to the lane-keeping system. Physical damage from road debris, water ingress, corroded connectors or failed internal electronics will necessitate a replacement.
Installation Recommendation
- Park the vehicle on a level surface and ensure ignition is off. For safety, isolate the vehicle electrical system according to workshop procedures.
- Remove the appropriate wheel arch liner or trim to access the sensor mounting point. Be prepared for a seized or sheared mounting screw; penetrating oil and extraction tools, or careful drilling, may be required.
- Disconnect the electrical connector gently and inspect for corrosion or damaged pins before fitting the new sensor.
- Fit the replacement sensor and secure with new fasteners if the original is damaged. Avoid overtightening; follow manufacturer torque values when available.
- Restore wiring and bodywork, then perform system checks. A diagnostic tool may be required to clear fault codes and perform final calibration or reinitialisation of the lane-keeping system.
Why This Part Most Commonly Fails
The most frequent causes of failure are mechanical damage and environmental exposure: moisture ingress, corrosion of the connector, impact from road debris, and mechanical stress at the mounting point. The mounting screw can become seized or break, complicating removal and increasing the chance that the sensor or surrounding components are damaged during service.
Technical Information
- Manufacturer: Stellantis / Citroën / Peugeot
- Model: Citroën C4, Citroën C4 Picasso, Citroën C5, Citroën C5 X7, Citroën C6, Peugeot 308, Peugeot 407
- Product Codes: 9659847480
- Additional Numbers: 603.014, 6590W1
Suitable for mechanics and competent DIYers, this AFIL sensor replacement helps restore lane-monitoring functionality and reduces false warnings once correctly installed and calibrated. When removing a seized screw, use appropriate extraction methods to avoid further damage to the sensor housing or wheel arch.
