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Replacing the compressor pulley > < Test conditions:

Leon Mk2

Checking
Checking
–  Measure the ambient temperature (must be greater than 15°C).
–  Close doors, bonnet, windows and sun roof.
–  Close “right” and “left” air inlets on the dashboard.
–  Switch on ignition.
–  Select operating mode “Econ” on the -E87- (the light on the “Econ” button lights up).
–  Start engine.
–  Begin climate control self diagnosis → Vehicle diagnosis, testing and information system VAS 5051
–  Select the function “Read measurement values block” and the indication group “012” → Vehicle diagnosis, testing and information system VAS 5051
–  Check the indications in the fields:
–  The field “4” shows 0% (the compressor is deactivated)
–  The field “4” shows that the pressure in the refrigerant circuit, at the measured ambient temperature, is the same or higher than the value in the table.
   
Ambient temperatura in °CIndicated pressure (bar of absolute pressure)
154,7
205,6
256,6
307,6
358,8

  Note
t  In absolute pressure 0 bar means a vacuum. The normal atmospheric temperature is, thus, about 1 bar of absolute pressure. In general, most manometer scales represent atmospheric pressure as 0 bar, meaning an absolute pressure of 1 bar (this can be recognized if there is a -1 on the scale).
t  The pressure in the refrigerant circuit depends on atmospheric temperature. Due to thermal radiation from the components (eg. the radiator for refrigerant liquid), with the engine service temperature, a slightly higher pressure than that specified for the corresponding ambient temperature will be indicated.
t  If the pressure indicated is less than indicated in the table:
–  Check the measured value of the high pressure sender for the air conditioning -G65-, “Electrical verification” → VAS 5051 Climatronic self diagnostics.
–  If it does not detect any fault in the high pressure sender, this means that there is very little refrigerant in the circuit.
–  Open the “Central” aerators on the dashboard.
–  Select the operation mode “Auto” in the -E87-.
–  Select the temperature range “LO” with the -E87-.
–  Adjust the direction of the air in the -E87- towards “Dashboard air outlets”.
–  Select the function “Read measured value block” and the indication group “008”.
–  Check the indications in the fields:
–  Indication field “4” a cycle proportion greater than 75% (the regulation valve -N280- is activated; the compresser is activated)
–  Check the indications in the fields:
–  Indication field “4” a cycle proportion greater than 75 % (the regulation valve -N280- is activated; the compresser is activated)
–  If you measure a current greater than 0.7 A (the current flows through the -N280-; the compressor is activated).
–  The pressure shown in the indication field “4” increases past this value when the compressor is deactivated.
  Note
t  If there is no current or it shows a very low current, check the energisation of the regulating valve for the compressor ⇒ “Electrical verification, test 5”.
t  If the pressure shown in the indication field “4” does not vary and the compressor is correctly energised (indication fields “3” and “4” of group 012), it means there is a fault in the refrigernat circuit. Send the vehicle to a workshop specialising in SEAT air conditioning.
–  Press the button for the air recirculation flap (the “air recirculation function” symbol on the button lights up).
–  Bring the engine speed up to 2,000 rpm (begin timing).
–  Select the function “Read measurement values block” → Vehicle diagnosis, testing and information system VAS 5051 ; indication group “007”.
   
–  Compare the value displayed in indication field 4 (corresponding to sender -G263-) with the values in the diagram.
A - Air temperature measured by the evaporator outlet temperature sender -G263-
B - Ambient temperature
C - Acceptable tolerance range
The air temperature measured should be within the specified tolerance range, according to the ambient temperature, after 5 minutes.
  Note
If these values are not reached, compare the measured values in fields “1” and “4”:
–  If the value in field “1” is lower than field “4” check the sender -G263-, verifying it is correctly fitted and that the electrical connections do not have contact resistances. if the sender is faulty, replace it.
–  If the measured value in field “1” is the same as field “4”, locate the fault if it differs from the theoretical value.
–  Compare the measured values indicated in fields “4” and “1” (corresponding to sender -G263- and to sender -G191-). The measured value in field “1” (of the outlet temperature sender -G191-) may be a maximum of 3°C higher after 5 minutes.
–  If the measured value in field “1” is more than 3°C higher than the value in indication field “4”, locate the fault if the temperature increases after the evaporator.
t  Temperature of air flow from “central” dashboard vents can also be measured using Minitester -SAT 4002-, for example.
t  The air conditioning function is, eg. to detect due to the fact that the refrigerant pipe cools at the low pressure side (wide duct).
t  If the sender temperature -G191- is too high, locate the fault if the temperature increases after the evaporator.
  Note
t  The pressure in the refrigerant circuit depends on different parameters. Neverthless, if the ambient temperature is between 20 and 25°C, the pressure generally does not exceed 20 bar. In extreme conditions (eg. in southern countries with high ambient temperatures, “driving in traffic queues” and in relatively high humidity) the pressure may reach 31 bar in virtue of the extremely high refrigeration performance involved in these cases.
t  At ambient temperatures below 25°C, the pressure in the refrigerant circuit does not usually exceed 16 bar (the refrigerant liquid fan operates at speed 1 and cools the condenser). So that the pressure can reach 16 bar, to activate speed 2 of the fan, you can briefly close the air inlets in the bonnet and bumper, for example.
t  Through the cycle proportion (indication field 4) the -E87- calculates the prevailing pressure in the refrigerant circuit.
t  If the cycle proportion is lower than 12.5% (equivalent to about 1.5 bar absolute pressure) and greater than 87.5% (equivalent to about 32 bar absolute pressure) the -E87- does not activate the compressor (the regulating valve is not energised -N280-). The compressor is only re-activated after the cycle proportion exceeds 12.5% (equivalent to 1.5 bar absolute pressure) or had dropped below 84% (equivalent to 29 bar absolute pressure).
t  So that it is not necessary to deactivate the compressor repeatedly due to excessively high pressure in the refrigerant circuit or an excessive refrigerant liquid temperature, the -E87- limits its performance:
t  As soon as the pressure in the refrigerant circuit exceeds 30 bar (absolute pressure) (maximum compressor performance will not be enabled until the pressure has dropped below 27 bar).
t  As soon as the refrigerant liquid temperature exceeds 115°C (at 118°C it is fully deactivated).
t  If the pressure in the refrigerant circuit exceeds 32 bar (cycle proportion greater than 87.5%), the -E87- only re-activates the compressor when the pressure has dropped below 29 bar (cycle proportion below 84%)
  E80-0060

Replacing the compressor pulley > < Test conditions: