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O-rings for refrigerant circuit > < Pin allocation on the High pressure senderG65

Leon Mk2

The pressure signal of the High pressure sender G65.
The pressure signal of the High pressure sender -G65-.
   
-A- Pressure in the high pressure side of the refrigeration agent circuit in bar (absolute pressure)
-B- Provides the duty cycle of the rectangular wave signal
-C- Characteristic curve
  Note
t  The Climatronic control unit -J255-/Air conditioning control unit -J301- activates the compressor when there is no condition to deactivate the compressor (activating the Compressor regulation valve, air conditioning -N280-) → Vehicle diagnostic, testing and information system VAS 5051.
t  With a duty cycle greater than 12 % (equivalent to approx. 1.2 bar absolute pressure) and less than 78 % (equivalent to about 32 bar absolute pressure).
t  If duty cycle is less than 12 % or greater than 78 %, the compressor is not activated (the Compressor regulation valve, air conditioning -N280- is not activated).
t  The duty cycle and the calculated pressure on the control and indication panel Climatronic control unit -J255-/Air conditioning control unit -J301- is displayed on the measurement values block → Vehicle diagnostic, testing and information system VAS 5051.
t  An absolute pressure of 0 bar represents an absolute vacuum. The normal ambient pressure is therefore equivalent to approx. 1 bar absolute pressure. In general most manometer scales represent atmospheric pressure as 0 bar meaning an absolute pressure of 1 bar (this can be recognised if there is a -1 on the scale).
  A87-0340
t  The Climatronic control unit -J255-/Air conditioning control unit -J301- sends a signal along the comfort data bus to the engine control unit, depending on the pressure calculated in the refrigeration circuit, while the compressor is activated, to request a higher refrigerant ventilator speed. The request calculated by the Climatronic control unit -J255-/Air conditioning control unit -J301- is displayed on the measurement values block → Vehicle diagnostic, testing and information system VAS 5051.
t  Currently, the request for a higher refrigerant ventilation speed is sent for the following duty cycle:
t  Pressure in the refrigerant circuit lower than approx. 9 bar (6 bar when the pressure was more than 9 bar) without requirement.
t  Pressure in the refrigerant circuit higher that approx. 9 bar (6 bar) to approx. 20 bar, depending on the pressure of 30 to 100 % of the requirement.
t  Pressure in the refrigerant circuit higher than approx. 20 to 100 % of the requirement.
t  The signal generated by the High pressure sender -G65- may also be used for engine management. The control and indication panel Climatronic control unit -J255-/Air conditioning control unit -J301- sends the information over the comfort system data bus to the engine control unit (the torque required for compressor operation depends on the pressure in the refrigeration circuit). Depending on engine control unit version, signal is displayed as duty cycle in measurement value block → Vehicle diagnostic, testing and information system VAS 5051
  A87-0340
This image appears on the screen of the oscilloscope (for example in the self diagnosis -VAS 5051-) when the limit conditions are fulfilled:
–  When the ignition is turned on (positive on the pin „3“ and earth on the pin „1“ on the High pressure sender -G65-).
–  Oscilloscope adjustment: 5 V/Div. = (5V per DC voltage unit) 5 ms/Div. (5 milliseconds per unit).
–  Measurement cable (signal cable) on the pin „2“ connected to the High pressure sender -G65-.
–  Measurement cable (screened) to contact „1“ (earth on High pressure sender -G65-).
  Note
t  The figure shows that the signal that is being transmitted when a pressure of approx. 7 bar absolute pressure is applied to the refrigeration circuit that is equivalent to a duty cycle of 25% (setting when the engine is stationary, an ambient temperature of 30℃ and a correctly filled refrigerant circuit).
  A87-0375
t  The amplitude of the pulses -A- depends on the pressure in the refrigeration circuit (if the pressure increases, the margin is made wider -A-).
t  The length -B- of the signals is always 20 milliseconds (corresponding to a frequency of 50 Hertz).
t  The duty signal is the result of the relationship between the width of the pulse -A- and the length of the signal -B-.
  A87-0375
t  For this test, the test cables from the auxiliary measurement set -VAG 1594C- may be used as can a cable adapted for this purpose. This requires, for example, one connector -A- or -B- each (with original part number 1J0 973,703 and 1J0 973,803 and the corresponding plug contacts), two commercially available sockets for banana plugs -C- and two wires with a cross section of 0.5 mm2.
  A87-0638

O-rings for refrigerant circuit > < Pin allocation on the High pressure senderG65