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Checking the pressure signal from the high-pressure sender G65 > < Test steps 5 to 9

A2

Test step 5:
Test step 5:
Pressure signal from the high-pressure sender -G65-
   
Vehicle diagnostic, testing and information system -VAS 5051-, measurement mode: DSO (Digital Storage Oscilloscope)
Setting: 5V/Div =, 5 ms / Div (5 VDC and 5 milliseconds per unit)
l  Adapter -V.A.G 1598/12- connected
Test stepTest box -V.A.G 1598 A- socketBeing tested:
l  Test conditions
–  Additional operations
SpecificationRemedies if the specification is not attained
5.17
and
14		Pressure-dependent square-wave signal from the high-pressure sender -G65-
l  Ignition on
–  Square-wave signal (as a function of pressure in the refrigerant circuit) → Chapter
t  Signal ratio greater than 16.5% and less than 50 %
l  No detectable signal
–  Using the current flow diagram, locate and rectify an open circuit, contact resistance or short circuit between the operating and display unit for air conditioner/Climatronic -E87- and the high-pressure sender -G65-
–  Check the voltage supply and earth connection to the high-pressure sender -G65- → Chapter.
–  Replace the high-pressure sender -G65-
     
l  Signal ratio under 5 % and over 95 %
–  Check the voltage supply and earth connection to the high-pressure sender -G65- → Chapter.
–  The high-pressure sender -G65- is defective; replace it
l  Signal ratio at or above 5 % or under 16.5 %
–  Not enough refrigerant in the circuit, the vehicle must be taken to a specialist air conditioner workshop
     
l  Signal ratio over 50 % or under 95 %
–  The high-pressure sender -G65- is defective; replace it
–  Fault in the refrigerant circuit, the vehicle must be taken to a specialist air conditioner workshop

  Note
t  The pressure and, thus, the signal ratio change with the ambient temperature if the refrigerant circuit has been filled with the correct amount of refrigerant.
t  The signal ratio and the pressure calculated by the operating and display unit for air conditioner/Climatronic -E87- are displayed in the measured value block in display group “001” → Chapter
t  The signal which is transmitted at a refrigerant circuit pressure of approx. 6 bar absolute is equivalent to a signal ratio of approx. 22 % (automatic adjustment with the compressor at a standstill, at an ambient temperature of 20 °C, and with a properly filled refrigerant circuit).
t  The signal which is transmitted at a refrigerant circuit pressure of approx. 16 bar absolute is equivalent to a signal ratio of approx. 47 %. When the compressor is not running, this is only the case under extreme conditions, e.g. at very high ambient temperatures and when the engine is hot.
   

Checking the pressure signal from the high-pressure sender G65 > < Test steps 5 to 9