Exhaust Gas Recirculation: Testing and Inspection

Special Tools, Testers And Auxiliary Items:
- VAG1527B voltage tester
- VW1594 connector test kit
- Wiring diagram

Test Conditions:
- Engine oil temperature 50°C (122°F) minimum

Checking Function:
- Start engine and let idle.





^ EGR valve diaphragm rod is pulled toward vacuum hose connector.
^ Diaphragm rod visible through opening (arrow) means exhaust gas is being supplied.
- Slowly increase engine speed, when engine speed exceeds 1200 RPM, EGR is interrupted for 2 seconds.
Diaphragm rod moves toward intake manifold for 2 seconds then moves back toward vacuum connection
- Continue to raise engine speed until part throttle switch closes.
Diaphragm rod moves back toward intake manifold means EGR is interrupted.

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

Checking Activation:
- Switch ignition off.





- Disconnect 2-pin harness connector -2- from two-way valve for EGR -N161- (item -1-).
- Connect VAG15278 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. Testing and Inspection
- Check EGR valve. Testing and Inspection

If control is NOT OK:
- Check engine coolant temperature sensor.
- Check EGR part throttle switch. Testing and Inspection

If no malfunction is detected for engine temperature sensor or for EGR part throttle switch:
- Check wiring diagram, or replace automatic glow time control module -J179-, if necessary.