EGR System, Checking

EGR SYSTEM, CHECKING

Special tools, testers and auxiliary items
- VAG 1527B LED Tester
- VW 1594 adaptor kit
- Wiring diagram

Test conditions
- Engine oil temperature 50 °C minimum

Functional check
- Start engine and let idle





- EGR valve diaphragm rod is pulled toward vacuum hose connector (observe diaphragm rod through opening -arrow-) = Exhaust gas is being supplied
- Slowly increase engine speed, when engine speed exceeds 1200 rpm, EGR is interrupted for 2 seconds (diaphragm rod moves towards intake manifold for 2 seconds then moves back again toward vacuum connection)
- Continue to raise the engine speed until the part throttle switch closes (membrane rod moves back towards intake manifold) = EGR is interrupted

If EGR does not work as described
- Check activation as follows

Activation, checking
- Switch off ignition





- Disconnect 2 pin harness connector -2- from EGR two-way valve N161, -1-
- Connect VAG 1527B LED Tester using jumper cables from the VW 1594 adaptor kit to the 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 the EGR Part Throttle switch closes
- LED must go out

Control OK
- Check EGR two-way valve, refer to "EGR Two-Way Valve, Checking". Testing and Inspection
- Check EGR valve. EGR Part Throttle Switch, Checking and Adjusting

Control not OK
- Check Engine Coolant Temperature sensor, Engine Coolant Temperature Sensor, Checking
- Check EGR Part Throttle switch

If no malfunction is detected for the Engine Coolant Temperature sensor or for the EGR Part Throttle switch
- Check wiring using wiring diagram, or replace automatic glow period Control Module J179 if necessary