Audi Workshop Service and Repair Manuals

Checking charge pressure Special tools and workshop equipment required

t  Vehicle diagnosis, testing and information system -VAS 5051- Procedure l  All hoses, pipes and wiring are checked for tight fit and leakages. l  No leaks in the intake and exhaust systems. l  No faults on engine or injection system (e.g. compression pressure or injector units). l  Coolant temperature at least 80 °C. l  Fault memory interrogated.   WARNING To avoid accident risks when road testing the vehicle with test equipment, always observe the relevant safety precautions → Chapter.

–  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 “08 - Read measured value block”.

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- –  Accelerate vehicle in 3rd gear from 2000 rpm at full throttle and observe rev counter. –  Press “Print - Save result” on -VAS 5051- at approx. 3000 rpm.

Display zone	Display	Specification
-1-	Engine speed	2800 ... 3200 rpm
-2-	Specification (charge pressure)	1650 ... 2200 mbar
-3-	Actual (charge pressure)	1650 ... 2100 mbar
-4-	Signal ratio of charge pressure control solenoid valve -N75-	40 … 95 %

–  Exit function “08 - Read measured value block” by pressing the ← key. –  Press “06 - End output”. –  Switch off ignition. If charge pressure in display zone -3- is not within the specified range: –  Check charge air system for leaks. –  Test vacuum actuation at turbocharger → Chapter. –  Check charge pressure control solenoid valve -N75- → Vehicle diagnosis, testing and information system VAS 5051. If all the above items are OK, but the charge pressure is too low: –  Renew turbocharger → Chapter.