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Information on the status
of the compressor
... displays whether the compressor is switched on or off. Switched on means
that the compressor is within the control range, in other words, a current of
300 – 800 mA is flowing through the compressor.
Speed increase ... is transmitted from the air conditioning system to the motor if the air
conditioning system needs an increased heating or cooling capacity. This
message is not related to the compressor status.
Refrigerant pressure The air conditioning system reads the pressure sensor and sets the signal to
CAN-Convenience. The determination of the refrigerant pressure occurs every
100 ms.
Radiator fan control Subject to the required condensor cooling, the air conditioning system issues
a "radiator fan control". This value can lie between 0 and 100 %. This value
depends on the refrigerant pressure and the information on petrol / diesel
engine from the diagnosis interface for data bus J533.
Power reduction of air
conditioner compressor
A reduction of the compressor power is possible by means of the externally
controlled compressor. The aim here is that the engine electronics control
unit J623 uses this infomation and only completely shuts down the
compressor in critical situations.
Compressor torque
transmission
The air conditioning system informs engine electronics control unit J623 of
the torque the compressor takes from the engine. Climatronic control
unit J255 considers the engine and compressor speed transmission ratio of
the various engines. The necessary information on the number of cylinders is
provided by the message from diagnosis interface for data bus J533.
Rear window heating This message signals to the control unit for on-board power supply J519 that
the rear window heating is to be switched on and this unit then takes over the
power control of the rear window heating.
Left/right sun sensor The amount of sunlight penetration measured by the sun sensor in W/m²
is supplied by the CAN-Convenience.
Seat heating This message transmits the different levels of seat heating left or right.
In the versions without seat heating level 0 is always transmitted.
Auxiliary heating The auxiliary heating can be switched on directly from Climatronic control
unit J255 via the auxiliary heating BIT. Climatronic control unit J255 transfers
the decision on the activation of auxiliary heating or auxiliary ventilation
via the "Auxiliary ventilation indicator light" bit.
In/output signals at Climatronic control unit J255
CAN-Convenience output signals
