Audi Workshop Service and Repair Manuals

Checking vacuum actuation at turbocharger Special tools and workshop equipment required

t  Turbocharger tester -V.A.G 1397 A-

t  Vehicle diagnosis, testing and information system -VAS 5051-

Procedure –  Disconnect hose going to vacuum unit for charge pressure control at separating point. –  Switch on turbocharger tester and set measuring range selector switch to position -I- (absolute pressure). –  Attach test hose to connection -I-. –  Connect test hose to detached vacuum hose.

–  Connect up vehicle diagnostic, testing and information system -VAS 5051- with diagnosis lead -VAS 5051/5A- and select vehicle self-diagnosis and vehicle system “01 - Engine electronics”. Engine must be idling.

Display on -VAS 5051- –  From list -1- select diagnostic function “04 - Basic setting”.

Display on -VAS 5051- –  Enter “011” via keypad -2- to select “Display group 011” and confirm entry with the Q key. 1 -  Enter display group

Display on -VAS 5051- –  Activate basic setting by touching button A.

l  The idling speed is increased to 1350 rpm ... 1450 rpm. l  The vacuum unit for charge pressure control is actuated in intervals. l  Specification on turbocharger tester -V.A.G 1397 A-: above 650 mbar vacuum when vacuum unit is actuated.   Note The absolute pressure displayed on the turbocharger tester -V.A.G 1397 A- must decrease by the specified value given. If specification is not obtained: –  Check whether hoses for charge pressure control have become disconnected or are obstructed → Chapter. –  Check charge pressure control solenoid valve -N75- → Vehicle diagnosis, testing and information system VAS 5051. If vacuum does not drop when actuation stops: –  Check the vent hoses → Chapter. –  Exit function “04 - Basic setting” by pressing the ← key. –  Press “06 - End output”.