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Engine code AHF, ALH, ASV > < Checking charge pressure control

Golf Mk4

Engine code AGR
Engine code AGR
Engine code AHF, ALH, ASV → Chapter
Test prerequisites
In order to check the function of charge air control, it is necessary to first determine the charge pressure without charge pressure control.
l  No fault stored in fault memory → Rep. Gr.01
l  No leaks on intake and exhaust systems
l  Control line to wastegate is not blocked, loose or leaking.
l  No faults in engine and fuel injection system, e.g. commencement of injection, injectors and compression pressure.
l  Engine oil temperature at least 80 °C
Test procedure
Note the following if testers and measuring instruments have to be used during a road test:
t  Test and measuring instruments must always be secured to rear seat and operated by a second person from this location.
If test and measuring instruments are operated from front passenger seat and the vehicle is involved in an accident, it is possible that the person sitting in this seat may receive serious injuries when the airbag is triggered.
–  Charge pressure is measured with fault reader -V.A.G 1551- or vehicle diagnosis tester -V.A.G 1552- with cable -V.A.G 1551/3- during a road test.
   
–  Pull connector -2- off charge pressure control solenoid valve -N75--1-.
–  Connect fault reader -V.A.G 1551- or vehicle diagnosis tester -V.A.G 1552- with cable -V.A.G 1551/3- (V.A.G 1552) and select engine electronics control unit with “address word” 01. The engine must be at idle when doing this: → Rep. Gr.01
  N21-0019
Indicated on display:
–  Press keys 0 and 8 for “Read measured value block” function and confirm with Q key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 01 and 1 for “Display group number 11” and confirm with Q key.
  
Read measured value block           HELP
Input display group number XXX
–  Indicated on display:
–  Accelerate vehicle in 3rd gear from approx. 1500 rpm to full throttle.
–  At approx. 3000 rpm, press PRINT button on fault reader -V.A.G 1551- or vehicle diagnosis tester -V.A.G 1552- .
  
Read measured value block 11           ->
840 rpm     938 mbar    978 mbar    92 %
Specification in display zone 3: 1550…1750 mbar
If charge pressure is not reached:
–  Check wastegate pressure unit and renew if necessary.
–  Check vacuum hoses → Chapter.
–  Repeat charge pressure test.
If charge pressure is still not reached:
–  Replace turbocharger.
If the charge pressure is exceeded:
–  Check charge pressure control solenoid valve -N75-. (Hose from turbocharger via valve to pressure unit not blocked when connector is pulled off).
–  Check vacuum hoses → Chapter.
–  Check wastegate pressure unit and actuating rod and renew if necessary.
–  Check wastegate shaft mounting in turbocharger for ease of movement. If corroded (seized), renew turbocharger.
–  If measured charge pressure is OK, repeat charge pressure test with charge pressure control:
–  Charge pressure control solenoid valve -N75- connector fitted.
–  Connect fault reader -V.A.G 1551- or vehicle diagnosis tester -V.A.G 1552- with cable -V.A.G 1551/3- (V.A.G 1552) and select engine electronics control unit with “address word” 01. The engine must be at idle when doing this: → Rep. Gr.01
  
Read measured value block 11           ->
3090 rpm     1866 mbar    1650 mbar    62 %
Indicated on display:
–  Press keys 0 and 8 for “Read measured value block” function and confirm with Q key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 0, 1 and 1 for “Display group number 11” and confirm entry with Q key.
  
Read measured value block           HELP
Input display group number XXX
–  Indicated on display:
–  Accelerate vehicle in 3rd gear from approx. 1500 rpm using full throttle.
–  At approx. 3000 rpm, press PRINT button on fault reader -V.A.G 1551- or vehicle diagnosis tester -V.A.G 1552- .
  
Read measured value block 11         ->
840 rpm    938 mbar   978 mbar   92%
Specification on fault reader -V.A.G 1551- or vehicle diagnosis tester -V.A.G 1552-: 1700…2200 mbar (in display zone 3)
If the specification is not attained:
–  Check charge pressure regulation solenoid valve -N75- → Chapter.
–  Check vacuum hoses → Chapter.
  
Read measured value block 11           ->
3090 rpm     1866 mbar    1917 mbar    62 %

Engine code AHF, ALH, ASV > < Checking charge pressure control