Lamp Control and Monitoring

Lamp Control and Monitoring

Power Limitation

In order to increase their service life, the incandescent vehicle lamps are activated using PWM once the system voltage rises above a coded value.

Any further increase in the system voltage results in constant voltage operation not to exceed 13.5 volts.

Dynamic PWM correction

The short-term peak loads of the Valvetronic unit create voltage dips in the vehicle electrical system, which in turn can result in fluctuations in the vehicle lighting. In order to reduce this effect, the LM incorporates adapted measures which compensate for this by performing a fast PWM correction.

Bulb Monitoring

All bulbs with the exception of the LED brakehail lights and the xenon headlights are cold monitored. The LEDs and bi-xenon lights are warm monitored along with the rest of the bulbs.

The LM signals the instrument cluster if a bulb has failed so that it can display a Check Control warning to the driver.

See the E65/E66 Instrument Cluster module of the iDrive for detailed descriptions of the CC warning messages.

Brake Force Display

As an indication of heavy vehicle braking or when the ABS is in regulation, the tail lights lights mounted on the luggage compartment lid illuminate at the same intensity as the brake lights.

It is activated by the LM recognizing a rapid change in acceleration and ABS operation.