Display Group 014
Display Group 014
Activation of the coolant fan(s) ( V7), signal from the air quality sensor (G238 ), and fresh air mode or recirculation mode request from the Climatronic control module (J255) A/C control head.
• The request to switch on the coolant fan(s) (V7) is sent by the Climatronic control module (J255) A/C control head as long as no compressor shutoff condition not allowing activation of the compressor is present (activation of the A/C compressor regulator valve (N280)) (e.g. engine not running or " Econ" operating mode selected).
• The coolant fan(s) (V7) is/are continuously regulated by the coolant fan control module (J293). The coolant fan control module (J293) is activated by the respective engine control module. The engine control module is activated by the Climatronic control module (J255) A/C control head via the comfort and powertrain data bus system to switch on the coolant fan(s) (V7). Refer to => [ Display Group 001 ] Measured Value Blocks for Display Groups 001 Through 010.
• Depending on the version of the Climatronic control module (J255) A/C control head, the coolant fan is switched on immediately in A/C system mode when the compressor is switched on or the coolant fan is only activated when a pressure of approx. 9 bar is exceeded in the refrigerant circuit.
• The engine control module activates the coolant fan control module (J293) (and thus the coolant fan(s) (V7)) only when the engine is running.
• The request to switch on the coolant fan(s) (V7) is sent by the Climatronic control module (J255) A/C control head to the engine control module. 100% is currently first required at a pressure of approx. 26 bar in the refrigerant circuit.
Explanation of the requests from the air quality sensor (G238) in display field "3" of display group "014"
• Oxidizable gases are for example carbon monoxide, benzole, hexane, etc.; these react with the oxygen in the air and are present in the exhaust gases of gasoline engines.
• Depending on the hardware/software version of the Climatronic control module (J255) A/C control head, vehicles without an air quality sensor (G238) have no display or show the message "not installed".
Explanation of the requests for fresh air mode or recirculation mode in display field "4" of display group "014"
* Depending on the hardware/software version of the Climatronic control module (J255) A/C control head, " 11", "12" or "13 " may also be displayed even though no request is made by the air quality sensor ( G238) for the recirculation mode due to the air quality. Therefore, observe display field "3".
• If there is no request for the recirculation mode, "00" instead of "0" can also be displayed.
• To prevent the windows from fogging up, the "automatic recirculation " function is limited to approx. 15 seconds when the compressor is off.
• If there is a fault at the air quality sensor (G238 ), "automatic recirculation mode" is not possible.
• In order to clear fogged up windows as quickly as possible, recirculation mode is not possible in the "defrost mode".
• The purpose of the air quality sensor (G238) is to keep temporarily high concentrations of pollutants (load peaks) in the outside air out of the passenger compartment. This is performed in that the Climatronic control module (J255) A/C control head switches the equipment from the fresh air mode to the recirculation mode after receipt of a request from the air quality sensor (G238).
• If the outside air pollution load remains high for a longer period of time, the air quality sensor (G238) starts to adapt to the changed environmental conditions through an adaptation program (learning program). An air recirculation request in evenly polluted ambient air is therefore generally shorter than 12 minutes. If a succession of peaks in the polluted air is detected, the air conditioning system can operate over a longer period of time in recirculated air mode.
• The "partial recirculation mode" function was introduced to improve the level of comfort. When switching the mode of the A/C system, the operation noise of the fresh air blower changes; changing the sequence (the flaps are activated consecutively instead of simultaneously) eases the transition.
• The A/C system can remain in "partial recirculation mode" for a long period (in order to achieve effective cooling output at high ambient temperatures without the system running continuously in recirculation mode, for example).
• If there is no request for the recirculation mode, "00" instead of "0" can also be displayed.
• In order to clear fogged up windows as quickly as possible, recirculation mode is not possible in the "defrost mode".