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Home >> Volvo >> 2013 >> XC60 R Design AWD L6-3.0L Turbo VIN 90 B6304T4 >> Repair and Diagnosis >> Lighting and Horns >> Headlamp >> Description and Operation >> Automatic Headlamp Levelling And Active Headlamps >> Function

Function






Function

Automatic headlight levelling




For vehicles without Four-C (Continuously Controlled Chassis Concept), the position sensors (7/119, 7/121) for rear wheel suspension and front wheel suspension send information to the Central electronic module (CEM) (4/56) on vehicle angle as regards load conditions, acceleration and braking.
For vehicles with Four-C (Continuously Controlled Chassis Concept), the Suspension module (SUM) (4/84) transmits information to the Central electronic module (CEM) about vehicle angle as regards load conditions, acceleration and braking.
The Central electronic module (CEM) uses the information from the position sensors or suspension module (SUM) to calculate the actual angle for headlamp levelling.
The Central electronic module (CEM) transmits information on the actual angle to the left headlamp control unit (LHCU) and right headlamp control unit (RHCU) via serial communication. The actuator motors are then controlled by the left headlamp control unit (LHCU) or right headlamp control unit (RHCU), respectively, via an analogue signal.

Active headlights




Active headlamps are an intelligent headlamps system that optimizes lighting of the road surface at night by expanding the light beam. The motorized headlamps are controlled by the Central electronic module (CEM), which retrieves signals from the CAN network and, in some cases, from directly connected sensors.
For the active headlamp function to be activated the Central electronic module (CEM)(4/56) requires information about the vehicle speed, gear and steering wheel angle.
The Central electronic module (CEM) receives information from the following control modules:
- Brake control module (BCM) (4/16)
- information about vehicle speed
- Transmission Control Module (TCM) (4/28)
- information about the current gear (automatic gearbox)
- Steering wheel angle sensor module (SAS) (3/130)
- information about the steering wheel angle
- The Central electronic module (CEM) also used internal signals:
- information about the brake lamp switch (3/10) (manual gearbox)
- information from the twilight sensor (7/12)
The active headlamp function is only enabled if the following conditions are met:
- The vehicle must be in motion, that is, travel at a speed faster than 4 km/h.
- Reverse gear must not be engaged.
- No daylight light conditions.
Also, the function active headlamp must be activated. The function en active headlamp is deactivated/activated via the menu system in Infotainment control module (ICM) (3/281).
When the function is active, the Central electronic module (CEM) receives continual information on vehicle speed and steering angle. Vehicle speed is obtained from the brake control module (BCM) while steering angle information comes from the steering wheel angle sensor module (SAS) (3/130). This information enables the Central electronic module (CEM) to calculate the current turn-out of the light beam.

Tourist mode / Adjustment of the light distribution pattern (certain models only)
Tourist mode is an adjustment of the light distribution pattern which prevents dazzling oncoming traffic when driving abroad.
Via the menu system in Infotainment control module (ICM) (3/281), it is possible to adjust the light beam pattern that is relevant as well as reset the headlamps' light beam pattern for right or left-hand traffic.
To adjust the light distribution pattern the vehicle must be stationary and in ignition position II or with the engine running.

Lighting Bi-Xenon lamps
There is normally a 3 second delay between activation with the light switch or ignition on and the Bi-Xenon lamp coming on.
- As with normal headlamps, Bi-Xenon lamps remain off while the engine is cranking and come on once the engine is running.
- Each time voltage is supplied to the high voltage unit (from the central electronic module (CEM)), 3 1-second attempts are made to light the Bi-Xenon lamp.

Safety
- In the event of a short-circuit on the high tension side the power supply cuts in less than 10 ms
- If the high voltage circuit is broken (such as due to an open circuit, defective bulb or no bulb in the lamp socket), during each activation the system attempts to light the lamp for a period of 700 ms. During the period, there is high voltage across the high voltage unit.
- Approximate component temperatures during operation: High voltage unit= 130 °C, Bulb holder = 170 °C, Bi-Xenon-bulb= 400 °C.
- The glass body of the Bi-Xenon-lamp is filled with different gases and metal vapors which are under pressure. The lamp can explode as it is under gas pressure.

Warning!
- Follow the safety instructions and recommendations in VIDA carefully when working with high voltage.
- Use safety goggles when handling the bulb. Risk of explosion!
- The electrical system must be turned off before starting work.
- Risk of burn injury. The components operate at very high temperatures.

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