Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Position Sensor, Headlamp Levelling
Vehicles without Four-C (Continuously Controlled Chassis Concept) have two position sensors for automatic headlamp adjustment. The headlamps are adjusted vertically based on load and road conditions to reduce the risk of dazzling.
One position sensor is located next to the rear axle and is connected to the left-hand rear control arm by a linkage system. The other position sensor is next to the right-hand front axle and is connected to the right-hand front control arm by a linkage system. This linkage system affects the sensor, allowing the angle of the car to be gauged.
The position sensors are directly connected to the headlamp control module (HCM). Each position sensor has three connections. Two are used for power supply and ground. One is used for signals on vehicle angle. When the ignition switch is in position II, level control is active and the sensors are used to calculate the average vehicle angle. At about 4 km/h (2.5 mph), dynamic level control is activated, which also makes quick corrections during acceleration and braking. In addition to vehicle speed in excess of about 4 km/h (2.5 mph), darkness is required.
The position sensor can be calibrated using the diagnostic tool. The calibration is saved in the headlamp control module (HCM) and must be performed again upon replacement of the control module or position sensor.
Vehicles with Four-C (Continuously Controlled Chassis Concept) use the signal from the suspension module (SUM) instead.
There are diagnostics for the position sensors.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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