Lens heating

The lens of the ACC sensor is made of plastic. The built-in lens heating ensures better availability of the Active Cruise Control option in winter weather conditions.

The lens heating is activated by the ACC sensor. The heating is controlled via a pulse-width modulated signal (PWM signal). The heating coil is integrated into the lens of the ACC sensor

The lens heating is only activated within a certain ambient temperature range (approx. +5 °C to -5 °C). Reason: Only at temperatures around zero is snow wet or moist. At temperatures well below this, snow will be dry. To prevent snow from thawing on the lens and creating an artificial coating, the heating is switched off below a certain ambient temperature. The current ambient temperature value is transmitted by the instrument cluster.

• Conditions for activation 
  • Engine ON
  • ACC ON
  • Ambient temperature between -5 °C and +5°C
• Safety cutout 
  • Temperature in ACC sensor over 50 °C

    (measured by interior temperature sensor in ACC sensor control unit)

  • Voltage greater than 16 volts

  The safety cutout shuts down the lens heating. The Active Cruise Control option remains activated. (No fault memory entry)

• Monitoring 

The lens heating is monitored for open and short circuits in the heating coil.

If the monitoring reports a fault, the Active Cruise Control option will be shut down. (Fault memory entry)