Checking activation

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1999 Volkswagen Jetta, 1998 Volkswagen Jetta, 1997 Volkswagen Passat, 1997 Volkswagen Jetta, and 1996 Volkswagen Passat. However, it is still accessible from the selected car via links, so may be relevant.

Switch ignition off.
Disconnect 2-pin harness connector -2- from two-way valve for EGR -N161- (item -1-).

Fig 1: Disconnecting 2-Pin Harness Connector From Two-Way Valve For EGR (Engine Code AAZ)
Connect VAG1527B voltage tester using jumper cables from VW1594 connector test kit to connector terminals.
Start engine and let idle.
- LED must light up
Slowly increase engine speed.
- LED must go out for 2 seconds and then light up again
Continue to increase engine speed until EGR part throttle switch closes.
- LED must go out

If control is OK:

Check EGR two-way valve.
EGR TWO-WAY VALVE, CHECKING
Check EGR valve.
EGR VALVE, CHECKING

If control is NOT OK:
Check engine coolant temperature sensor.
ENGINE COOLANT TEMPERATURE SENSOR, CHECKING
Check EGR part throttle switch.
EGR PART THROTTLE SWITCH, CHECKING AND ADJUSTING

If no malfunction is detected for engine temperature sensor or for EGR part throttle switch:

Check wiring using appropriate System Wiring Diagrams article, or replace automatic glow time control module - J179-, if necessary.