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

A4 Cabriolet Mk2

Test step “5”
Test step “5”
Pressure signal from high-pressure sender -G65-
   
Vehicle diagnostic, testing and information system -VAS 5051A-, measurement mode: DSO (Digital Storage Oscilloscope)
Setting 5V / div DC, 5 ms / div (5 V DC and 5 milliseconds per unit)
l  Adapter cable -V.A.G 1598/12- connected
Test stepTest box -V.A.G 1598A- socketChecking of
l  Test conditions
–  Additional operations
SpecificationMeasures to be taken if reading does not match specification
5.17
+
13		Pressure-sensitive square-wave signal from high-pressure sender -G65-
l  Ignition on
l  Engine not running
l  Ambient temperature greater than 20 °C and less than 35 °C
–  Square-wave signal (as a function of pressure in refrigerant circuit) → Chapter
t  Duty cycle greater than 16.5 % and less than 50%
l  No signal detection
–  Check power supply and earth connection to high-pressure sender -G65- → Chapter.
–  Use current flow diagram to locate and eliminate open circuit in wiring, contact resistance or short circuit between operating and display unit, Climatronic control unit -J255- and high-pressure sender -G65-
–  Replace high-pressure sender -G65-

   
Vehicle diagnostic, testing and information system -VAS 5051A-, measurement mode: DSO (Digital Storage Oscilloscope)
Setting 5V / div DC, 5 ms / div (5 V DC and 5 milliseconds per unit)
l  Adapter cable -V.A.G 1598/12- connected
Test stepTest box -V.A.G 1598A- socketChecking of
l  Test conditions
–  Additional operations
SpecificationMeasures to be taken if reading does not match specification
5.1
(continued)		7
+
13		Pressure-sensitive square-wave signal from high-pressure sender -G65-
l  Ignition on
l  Engine not running
l  Ambient temperature greater than 20 °C and less than 35 °C
 
l  Duty cycle less than 5% or greater than 95%
–  Check power supply and earth connection to high-pressure sender -G65- → Chapter.
–  High-pressure sender -G65- defective, replace
l  Duty cycle greater than 5% and less than 16.5 %
–  Insufficient refrigerant in circuit, take vehicle to specialist air conditioner workshop

   
Vehicle diagnostic, testing and information system -VAS 5051A-, measurement mode: DSO (Digital Storage Oscilloscope)
Setting 5V / div DC, 5 ms / div (5 V DC and 5 milliseconds per unit)
l  Adapter cable -V.A.G 1598/12- connected
Test stepTest box -V.A.G 1598A- socketChecking of
l  Test conditions
–  Additional operations
SpecificationMeasures to be taken if reading does not match specification
5.1
(continued)		7
+
13		Pressure-sensitive square-wave signal from high-pressure sender -G65-
l  Ignition on
l  Engine not running
l  Ambient temperature greater than 20 °C and less than 35 °C
 
l  Duty cycle greater than 50% or less than 16.5%
–  High-pressure sender -G65- defective, replace
–  Fault in refrigerant circuit, take vehicle to specialist air conditioner workshop

  Note
t  If the refrigerant circuit is filled with the correct amount of refrigerant, the pressure and thus the duty cycle change with ambient temperature.
t  The duty cycle and the pressure calculated by the operating and display unit, Climatronic control unit -J255- are displayed in the measured value block (display group “001”) → Chapter.
t  The signal transmitted at a refrigerant circuit pressure of approx. 5 to 6 bar absolute corresponds to a duty cycle of approx. 22%, which is achieved with the compressor not running, at an ambient temperature of 20 °C and with the refrigerant circuit properly charged.
t  The signal transmitted at a refrigerant circuit pressure of approx. 16 bar absolute corresponds to a duty cycle of approx. 50 %. With the compressor not in operation, this is only achieved under extreme conditions (e.g. very high ambient temperatures and a hot engine).
   

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