Tail Lamp: Description and Operation

Tail Lights







NOTES: The lense area of the direction indicator light (4) is darker for the USA/Canadian market.

The tail lights on the Cayenne models as of model year 2008 are designed as a single unit and combine the indicator light, rear fog lights (left and right), backup light, brake light, marker light and reflector in one housing.

The following features have been added to further improve functionality and design:
- LED technology
- Side marker light
- New design

The most remarkable feature of the new tail lights is the use of 16 LEDs for the rear light and brake light as well as four other LEDs for the marker light. In addition to the visual impact and the long service life, the advantage of LED technology is above all the short response time. While the response time of conventional bulbs is approx. 100 ms, the response time for LEDs is around 0.1 ms.

At a speed of 60 mph (100 km/h), this difference is equivalent to a distance of approx. 3 feet. Earlier signalling of braking therefore means that traffic driving behind the vehicle is warned sooner. The tail light also has a side marker light with LEDs, which is positioned in the lower side section of the tail light.

Vehicle Electrical System Management

The main function of the vehicle electrical system control unit is to protect the battery against excessive cyclical loads. Since functions that are relevant to the driver are controlled by vehicle electrical system management and technical safety must be assured at all times, a lot of input data is required on the vehicle electrical system control unit. The status of the vehicle electrical system is mainly determined by comparing the determined voltage with the permitted lower voltage limit.

The status of the vehicle electrical system is determined from the battery voltage values and information relating to high current loads with a short "on" time. The load switching states currently requested by the driver are also stored in the vehicle electrical system control unit. The vehicle electrical system control unit communicates with the DME control unit in order to increase the idling speed if necessary for the purpose of improving the vehicle electrical system status.

Comfort loads can be switched off if necessary, i.e. if the vehicle electrical system status is too negative. The increased battery voltage is then made available to other control units via the CAN bus. Before load switch-off (e.g. plug sockets and cigarette lighter) is activated, the driver is alerted by the warning "Battery low" in the instrument cluster. Once the vehicle electrical system status is no longer critical, the loads are switched back on again in reverse order. Diagnosis of the vehicle electrical system control unit is performed using the PIWIS Tester.