Audi Workshop Service and Repair Manuals

Test requirements:

• ● Vehicle diagnostic, testing and information system VAS 5051 connected, vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected.

Test sequence

→ Display on VAS 5051:

• ‒ Under -1- select the diagnostic function "03 - Final control diagnosis".
• ‒ Actuate the solenoid valve for boost pressure limitation -N75.

• ◆ Solenoid valve for boost pressure control N75 should operate audibly.
• ◆ The boost pressure control linkage of the vacuum unit on the turbo charger should move to and from (at least 3 ... 4 times while there is a vacuum in the vacuum reservoir).

If linkage does not move because solenoid valve is not working:

• ‒ Check boost pressure control solenoid valve -N75 .
• ‒ Check all vacuum hoses are fitted and not leaking => from Page 21-20.

If linkage does not move, even though solenoid valve is working:

• ‒ → Connect hand vacuum pump V.A.G 1390 to boost pressure control valve and check that linkage moves freely between both end stops.

If the linkage moves, but the boost pressure specifications are not attained:

• ‒ Fit a new turbocharger => Page 21-55.

If the linkage does not move freely, or moves jerkily (uneven performance when vehicle is in operation):

• ‒ Fit a new turbocharger => Page 21-55.