Exterior lighting

Active main beam

Updated 7/23/2018

Active main beam is a function which uses a camera sensor at the top edge of the windscreen to detect the headlamp beams from oncoming traffic or the rear lights of vehicles in front, and then switches from main beam to dipped beam.

P5-1617 Stalk with turning ring in AHBC position

Active main beam is activated with the rotating ring on the stalk switch in position .

The function can also take streetlights into account. Main beam is reactivated when the camera sensor no longer sees any oncoming vehicles or vehicles ahead.

The function can start while driving in the dark when the car's speed is approx. 20 km/h (approx. 12 mph) or higher.

If active main beam is deactivated while main beam is on, the lighting is immediately reset to dipped beam.

When active main beam is activated, the symbol illuminates with a white glow in the driver display.

When main beam is activated, the symbol shines blue. This also applies for LED headlamps if the main beam is partially dimmed, i.e. if the light beam shines with slightly more than dipped beam.

Car with halogen headlamps

The lighting returns to main beam about a second after the camera sensor no longer detects the headlamp beams from oncoming traffic or the rear lights from vehicles in front.

Car with LED

LED (Light Emitting Diode)

headlamps*

If the active main beam has the on/off functionalityDepending on the car's equipment level. then the lighting returns to main beam about a second after the camera sensor no longer detects the headlamp beams from oncoming traffic or the rear lights from vehicles in front.

If the active main beam has adaptive functionalityDepending on the car's equipment level. then, unlike what happens during conventional dimming, the light beam continues to illuminate with main beam on both sides of oncoming traffic or vehicles ahead - only the part of the light beam that points directly to the vehicle is dimmed.

P5-1507 Principle AHBC2

Adaptive functionality: Dipped beam directly towards oncoming vehicle, but continued main beam on both sides of the vehicle.

The lighting returns to full main beam about a second after the camera sensor no longer detects the headlamp beams from oncoming traffic or the rear lights from vehicles in front.

Limitations for active main beam

The camera sensor on which the function is based has limitations.

P5-1519 Symbol Active HeadBeamTempUnavailable

If this symbol is shown in the driver display, together with the message Active High BeamTemporarily unavailable, then switching between main and dipped beam must be performed manually. The rotating ring on the stalk switch can still be in the position. The symbol extinguishes when these message are shown.

P5-1519 Symbol FactoryMode_104

The same applies if this symbol is shown together with the message Windscreen sensorSensor blocked, see Owner's manual.

Active main beam may be temporarily unavailable e.g. in situations with dense fog or heavy rain. When active main beam becomes available again, or the windscreen sensors are no longer blocked, the message goes out and the symbol illuminates.

Warning

Active main beam is an aid for using the optimum beam pattern when conditions are favourable.

The driver always bears responsibility for manually switching between main and dipped beam when traffic situations or weather conditions so require.


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