Exhaust Gas Recirculation: Testing and Inspection

Exhaust Gas Recirculation (EGR) valve and EGR temperature sensor -G98-, checking (California Only)

Check with VAG1 551 Scan Tool (ST) in "Read Measuring Value Block" function 08, testing closed throttle position.
^ VAG 1551 Scan Tool connected with "Read Measuring Value Block" function selected (display group 002).





Indicated on display
^ No leaks in vacuum lines and hose connections
^ Vacuum lines not plugged or kinked
^ Engine oil temperature minimum 50° C (122° F)





^ Disconnect EGR vacuum regulator solenoid valve -N18- (item -1-).
^ Connect VAG 1390 vacuum pump to disconnected hose.
^ Operate vacuum pump.
Performance at Closed Throttle Position (CTP) must get noticeably worse.
If NO:
^ Check lines and connections for obstructions and clean if necessary.
^ If necessary, replace EGR valve.
If idle gets worse:
^ Read EGR temperature in display field 4. Temperature must rise steadily without interruption.
If display reads 127.4° C, or if the temperature drops, there is an interruption.
^ As soon as the temperature value reaches 200° C, disconnect vacuum pump.
^ Press (arrow) button.
^ Press buttons -0- and -6- to select "End Output" function 06.
^ Press -Q- button to confirm input.
If temperature does not change:
^ Perform electrical testing, Refer to Fuel delivery and Air Induction.
If no malfunction is found:
^ Replace EGR temperature sensor -G98- go to Page 26-14.