General Information

General Information

Special tools, testers and auxiliary items required

• Vehicle Diagnostic Tester and the corresponding connection lines Workshop equipment.

• Standard thermometer (for temperature measurements, if necessary a thermometer with 2 measuring probes for simultaneous measurement for example for temperature at right and left)

• Refer to => [ Cooling Output Tests ] Cooling Output Tests.

• A start-stop system is available for certain engines of this vehicle as optional equipment. Depending on the setting on the Climatronic control module (J255) (and if present at the rear A/C display control head (E265) ) it can prevent the stop function. If, for example, the defrost mode is selected on the Climatronic control module, the stop function is not possible or will be interrupted and the engine will start as soon as this operating mode is selected. The same applies in the case of heating and cooling. The difference between the target and actual temperature is greater than a specified value. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• In this vehicle the Coolant recirculation pump (V50) is controlled not only when the stop function is active but also when the engine is running, for example at temperature preselection warm on the Climatronic control module (HI appears in the display of the Climatronic control module and the Multi Media Interface). In this vehicle, the Coolant recirculation pump is also activated to support the coolant pump of the motor. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

• In vehicles without a rear A/C unit (with a rear air distributor housing), the temperature of the air flowing from the front A/C unit to the rear air distributor housing is regulated by the Climatronic control module, so that an average temperature is set for the air from the vents in the front area. The target temperature for the air from the vents in the front area is calculated via the setting for the left and right side on the Climatronic control module by the Climatronic control module. However, if a setting which no longer regulates the temperature (for example HI for maximum heating or LO for maximum cooling) is present on the Climatronic control module, the temperature of the air from the vents in the front area is no longer regulated. If, for example, maximum heating HI is set on the Climatronic control module for one side and maximum cooling LO for the other side, the air for the vents in the front area is maximally heated.

• For vehicles where there is also the version with the rear air distribution housing, there is a rear Climatronic A/C display control head (E265) installed. The air temperature and the air volume calculated and regulated by the Climatronic control module (J255) is also influenced by the setting on the rear Climatronic A/C display control head, refer to=> [ Rear A/C Control Head (E265) ] Rear A/C Control Head (E265).

• Certain A/C system functions can be switched on and off via the MMI (Multi Media Interface) under the "A/C system" function in the "car"/"car systems" menu. The A/C system control can also be influenced via presettings in the MMI (Multi Media Interface) under the "A/C system" function in the "car"/"car systems" menu. Therefore, first check the presetting in the MMI in the case of a problem with these components. Refer to Infotainment/MMI operating instructions.