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Test the supercharging pressure control solenoid valve N75 > < Test conditions

Leon Mk2

Test process
Test process
If test and measurement apparatuses are needed during a road test, take into account the following:
t  The test and measurement apparatuses must be installed in the rear seat and operated by a second mechanic.
If the test and measurement apparatuses are operated from the front passenger seat, in the event of an accident the person occupying that seat could be injured by the airbag.
–  The supercharging pressure is measured with fault reader -V.A.G. 1551- during a road test.
To test the functioning of the supercharging pressure control, it is first necessary to determine the supercharging pressure without pressure control.
   
–  Remove the connector -2- from the supercharging pressure control solenoid valve -N75--1-.
–  Attach the -V.A.G. 1551- (-V.A.G.1552-) and, with the corresponding “address code” 01, select the engine electronics control unit. When doing so, the engine must be idling: → Vehicle diagnosis, testing and information system VAS 5051
  N21-0136
Reading on the display:
–  Press 0 and 8 for the function “Read measured value block” and press Q to confirm the entry.
  
Rapid data transmission             HELP
Select function XX
Reading on the display:
–  Press 0, 1 and 1 for the “display group number 11” and press Q to confirm the entry.
  
Read measured value block               
Enter value group number XXX
Reading on the display:
–  Vehicle in 3rd gear and accelerate to full gas from approx. 1,500 rpm.
–  At approx. 3,000 rpm press PRINT on the -V.A.G. 1551-.
  
Read measured value block 11           →
900 rpm   1020 mbar   1020 mbar    64 %
Target value in display field 3: 1375...1625 mbar
If the supercharging pressure is not reached:
–  Test the pressure unit for the supercharging pressure control valve, and replace if necessary.
–  Test the vacuum hoses → Chapter.
–  Retest the supercharging pressure.
If the supercharging pressure is still not reached:
–  Replace the exhaust turbocompressor.
If the supercharging pressure is exceeded:
–  Test the supercharging pressure control solenoid valve -N75- (continuity of flow: hose of the turbocompressor, valve, and until the pressure unit, with the connector detached).
–  Test the vacuum hoses → Chapter.
–  Test the pressure unit for supercharging pressure control valve and the control rod, and replace if necessary.
–  Check that the shaft works smoothly in its housing at the supercharging pressure control valve on the turbocompressor. If not, replace the turbocompressor.
–  If the measured supercharging pressure is OK, retest the supercharging pressure with supercharging pressure control functioning:
–  Connector attached to the supercharging pressure control solenoid valve -N75-.
  Note!
When the connector on the supercharging pressure control solenoid valve -N75- is detached faults are stored. Thus, consult the fault memory and clear.
–  Consult the fault memory: → Vehicle diagnosis, testing and information system VAS 5051
–  Attach the -V.A.G. 1551- (-V.A.G.1552-) and, with the corresponding “address code” 01, select the engine electronics control unit. When doing so, the engine must be idling: → Vehicle diagnosis, testing and information system VAS 5051
  
Read measured value block      11      →
3090 rpm   1866 mbar   1650 mbar   62 %
Reading on the display:
–  Press 0 and 8 for the function “Read measured value block” and press Q to confirm the entry.
  
Rapid data transmission             HELP
Select function XX
Reading on the display:
–  Press 0, 1 and 1 for the “display group number 11” and press Q to confirm the entry.
  
Read measured value block               
Enter value group number XXX
Reading on the display:
–  Vehicle in 3rd gear and accelerate to full gas from approx. 1,500/min.
–  At approx. 3,000 rpm press PRINT on the -V.A.G. 1551-.
  
Read measured value block 11           →
840 rpm    938 mbar    978 mbar    92 %
Target value on the -V.A.G. 1551-: 1800...2200 mbar (in display field 3).
If the target value is not reached:
–  Test the supercharging pressure control solenoid valve -N75- → Chapter.
–  Test the vacuum hoses → Chapter.
  
Read measured value block 11           →
3090 rpm   1866 mbar   1917 mbar   62 %

Test the supercharging pressure control solenoid valve N75 > < Test conditions