Audi Workshop Service and Repair Manuals

Checking exhaust gas recirculation Checking of exhaust gas recirculation is done with the vehicle diagnosis, testing and information system -VAS 5051- under the function “basic setting”. The EGR valve is pulsed every 10 seconds, so that the extreme values for the EGR (air mass meter -G70-) can be read. Special tools and workshop equipment required

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

Procedure l  Coolant temperature at least 80 °C. –  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-: –  Use keypad -2- to enter “003” for “Display group number 003” and confirm by touching 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. –  Check display in zones -2-, -3- and -4-. –  Press “Print - Save result” on -VAS 5051-.

Display zone	Display	Specification
-2-	Activation of exhaust gas recirculation valve -N18-	Display alternates at 10 second intervals: “EGR active” and “EGR inactive”
-3-	Intake air mass	Display alternates at 10 second intervals: Difference min. 100 mg/H
-4-	Duty cycle exhaust gas recirculation valve -N18-	Display alternates at 10 second intervals: “20 %” and “65 %”

–  Exit function “04 - Basic setting” by pressing the ← key. –  Press “06 - End output”. –  Switch off ignition. If the specifications are not obtained: –  Check mechanical exhaust gas recirculation valve  → Chapter. –  Check vacuum hose connections  → Chapter. –  Check exhaust gas recirculation valve -N18- → Vehicle diagnosis, testing and information system VAS 5051.