TT Quattro Coupe V6-3.2L (BHE) (2005)
react to variable A/C compressor loads dependant of refrigerant system pressure. This signal may or may not appear as a duty cycle on the read
measuring value block display.
High pressure sensor -G65-, checking signal
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Connect oscilloscope test leads to -G65- signal wire electrical testing, step 4.
The oscilloscope shows this signal pattern under the following conditions:
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Ignition switched on (-G65- connected to positive and GND).
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Oscilloscope settings: 2 V/Div. = (2 volts per grid division, direct current) 5 ms/Div. (5 milliseconds per grid division).
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Oscilloscope test lead (signal wire) connected to terminal 2 on -G65-.
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Oscilloscope test lead (shielding) connected to GND.
NOTE: Signal pattern illustrated corresponds to a refrigerant system pressure of approx. 5 bar (equivalent to a signal ratio of approx. 20%). This
is the pattern that occurs at an ambient temperature of 20 degrees C (68 degrees F) when the compressor is not running and the refrigerant circuit
is full.
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Pulse width -A- varies according to refrigerant system pressure. When the pressure rises, the pulse width increases.
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Interval -B- between signals is always 20 milliseconds.
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The signal ratio is the ratio between pulse width -A- and signal interval -B-.