Installation of the directional headlight on the Citroën C4: Calibration of the automatic leveling sensors.

Technical Diagnosis and Common Symptoms

The PSA bi-xenon directional headlight system (commercially known as Xenon Dual Function) in the Citroën C4 (Pallas, Hatch and VTR generations) is a complex system that goes beyond a simple bulb. Unlike the common halogen system, this one has a dedicated control module, internal stepper motors in the headlight, and two load/height sensors installed on the front and rear axles. The classic symptom of failure or need for calibration occurs when the warning light comes on.[glossary]SERVICE[/glossary]The light comes on in the dashboard and the headlights perform the initial check movement (down and to the sides), but remain pointed towards the ground, or when the lateral steering stops working in curves.

Frequently, when replacing shock absorbers or performing suspension work, the articulated arm of the leveling sensor is mounted upside down or disconnected, resulting in a voltage reading outside the operating range.[glossary]ECU[/glossary]lighting, shutting down the system for safety reasons.

Probable Causes and DTC Codes

When the system detects an anomaly, it stores specific fault codes that can be read via[glossary]OBD2[/glossary]In the Citroën C4, the responsible module is the Projector Directionnel (PDRL). The most common codes are:

• B1101: Front height sensor failure (inconsistent signal).
• B1102: Rear height sensor failure (open circuit or short circuit).
• B1105: The supply voltage to the stepper motors is out of range.
• B1108: Communication failure[glossary]CAN[/glossary]with the lighting calculator.
• U1113: Loss of communication with the[glossary]ABS[/glossary]/ESP (the headlight needs the wheel speed to calculate the turning angle).

Power Plant: Fuses and Relays

Before condemning the headlight motors or sensors, check the electrical integrity of the…[glossary]fuse[/glossary]dedicated. In the C4, the automatic leveling and steering system protection is usually located in the engine compartment fuse box (PSF1):

Step-by-Step Verification and Calibration

1. Mechanical Inspection of Sensors

The first step is to raise the vehicle on a four-post lift (to keep the weight over the wheels). The front sensor is attached near the left suspension arm, and the rear one in the center of the torsion beam. Check that the plastic rods are not broken or damaged.[glossary]torque[/glossary]The mounting bracket did not give way. The rod should form an angle close to 90 degrees with the sensor arm when the car is at rest.

2. Necessary Tools

• Automotive scanner compatible with PSA protocol (Diagbox/Lexia are ideal).
• Torx T20 and T30 keys.
• 10mm socket for mounting the sensors.
• Headlight adjuster (optical equipment) for initial physical adjustment.

3. Calibration Procedure (Height Learning)

1. Make sure the vehicle is on level ground, with properly inflated tires and a full tank of gas (or as specified in the service manual).
2. Connect the scanner to the OBD2 port located below the ashtray/center console.
3. Access: Diagnostic Menu > Lighting > Projector Calculator Directionnel > Telematics/Configuration.
4. Select “Zero Point Calibration”. The system will move the headlights to the extremes and center them.
5. The scanner will ask you to confirm the physically measured height value from the ground to the center of the headlight lens.

OEM Parts and Reference Codes

If a component is damaged, use the references below for replacement. Avoid parts from salvaged vehicles without warranty, as the internal mechanism of the xenon is sensitive to moisture and dust.

• Front Leveling Sensor: OEM 6224.G2 (Also replaces previous versions).
• Rear Leveling Sensor: OEM 6224.G3.
• Control Module (Ballast/ECU): OEM 6224.J2 or Valeo LAD5G (depending on the year/model).
• Xenon Lamp: D1S 35W (Brands like Osram or Philips are recommended to avoid electrical noise on the CAN network).

Approximate Costs in Brazil

Prices may vary depending on the state and stock availability.

• Height sensor (original): R$450.00 to R$800.00 each.
• Complete directional headlight (new original): It can exceed R$ 5,000.00 (rarely in stock).
• Calibration labor: Between R$250.00 and R$450.00 at specialized workshops.
• High-quality D1S bulb: Between R$350.00 and R$600.00 per unit.

When should I take it to the dealership or a specialist?

The Citroën C4’s directional headlight system requires Diagbox software for most component matching functions. If the error persists after replacing the bulb or sensor, the problem may lie with the…[glossary]relay[/glossary]Internal faults in the BSM (Engine Service Box) or a wiring harness failure requiring oscilloscope analysis. In these cases, a visit to a dealership or workshop with in-depth knowledge of French electronics is essential to avoid short-circuiting expensive modules like the BSI.

Prevention and Maintenance

To extend the lifespan, avoid high-pressure jet washing directly on the headlights, as this can damage the vents and cause condensation, burning out the internal stepper motors. Whenever performing any suspension service, advise the technician not to disconnect the load sensor rod without proper alignment during reassembly.