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Testing solenoid valve for boost pressure limitation > < Testing boost pressure - engine code AFF, 1Z

A4 Mk1

#Diesel direct injection and glow #plug system (4-cyl.)>06.97
Testing boost pressure system
Testing boost pressure - engine code AFN
 
21-096
  • ‒ → Boost pressure is measured in the course of a test drive with the turbocharger tester V.A.G 1397/A and the fault reader V.A.G 1551.

Test prerequisites:

  • ● No leaks in intake and exhaust system
  • ● Compression, hydraulic tappets and injectors OK
 
A23-0021
  • ‒ → Additionally connect measuring hose of turbocharger tester with T-piece to pressure conenction of intake manifold pressure sender and secure with hose clip.
  • ‒ Feed measuring hose over rear edge of bonnet and through right-hand window opening into passenger compartment.
 
21-096

Notes:

  • ◆ The hose connection must be absolutely tight to prevent measurement errors.
  • ◆ Make sure that measuring hose does not become trapped at the bonnet or side window.
  • ‒ → Switch on turbocharger tester, set measuring range switch to -I- and attach measuring hose to connection -I-.
Warning!
Second person is required to operate V.A.G 1397/A and V.A.G1551.
 
→ Read measured value block (function 08) and select display group 11, => Page .
Read measured value block 11     ⇒
840 rpm    938 mbar    978 mbar    92 %
  • ‒ Accelerate vehicle in 3rd gear from roughly 1500 rpm at full throttle.
  • ‒ At approx. 3000 rpm, simultaneously press memory button -M- on V.A.G 1397/A and PRINT button on V.A.G 1551.
    • Desired value on V.A.G 1397/A: 1.850...2.200 bar
     
    → Desired value on V.A.G 1551: 1850...2200 mbar (in display field 3)
    Read measured value block 11     ⇒
    3090 rpm    1948 mbar    1989 mbar    62 %

    Note:

    The boost pressure level is to be determined with the turbocharger tester V.A.G 1397/A. The fault reader V.A.G 1551 is designed to check whether the boost pressure has also been recorded in the control unit.

    If measured boost pressure is not OK:
     
    → Perform final control diagnosis and actuate solenoid valve for boost pressure limitation => Page .
    Final control diagnosis    ⇒
    Solenoid valve for boost pressure limitation -N75
    • Solenoid valve must operate (can be felt by touching valve)...
     
    A23-0022
      • ‒ If solenoid valve does not operate, test solenoid valve for boost pressure limitation -N75
    • ... and linkage of vacuum unit at turbocharger must move back and forth at least 3...4 times (as long as vacuum is present).
      • ‒ → If linkage does not move, connect vacuum hand pump V.A.G 1390 to vacuum unit and test freedom of movement of linkage.
      • ‒ If linkage moves freely, test vacuum hoses => Page 23-55.

    Testing solenoid valve for boost pressure limitation > < Testing boost pressure - engine code AFF, 1Z