Switch-on conditions

The active and passive air flap control is active as of terminal 15 ON.

The following evaluation criteria are used for the air flap control:

• Coolant temperature (coolant-temperature sensor and temperature sensor at the radiator outlet)
• Transmission oil temperature
• Engine oil temperature
• Application of current to the map thermostat
• Engine load signal
• Engine speed
• Road speed
• Speed of the electric fan
• Trailer detection

Special case: frost protection 

The following evaluation criteria are used for frost protection:

• Road speed
• Outside temperature
• Status signal of window wipers

Control operation is governed by fixed control variables in order to detect weather conditions in which slush is formed on the roads.

Otherwise, this slush would collect before the closed fins of the radiator shutter and might freeze. The frost protection opens the fins at an early stage, thus preventing the snow from collecting.

No liability can be accepted for printing or other faults. Subject to changes of a technical nature