EGR Control Solenoid: Testing and Inspection

PRE-TEST REQUIREMENTS
^ Engine coolant temperature at least 80°C (176°F).
^ All electrical consumers (including A/C) switched OFF.
^ Radiator fan must not run while performing tests.
^ Vacuum connections tight and without leaks.
^ Vacuum hoses not pinched or plugged.

EGR Frequency Valve:

TEST PROCEDURE
- Ignition switch OFF.
- Disconnect EGR frequency valve harness connector.
- Using suitable multimeter check resistance between frequency valve terminals.

^ Must be 25 - 35 ohms.
^ IF NOT replace EGR frequency valve.

Fig. 10 Checking Frequency Valve Duty Cycle:

- Using a test harness that allows the frequency valve to remain connected while testing (VAG 1594 or equivalent) connect VAG 1367 tester (or a suitable duty cycle meter) to the connectors as shown.
- START engine and raise RPM to about 2000.

^ Duty cycle should be 32° ± 10% at 2000 RPM.

NOTE: The duty cycle is first triggered at 1800 RPM. Therefore, duty cycle will not register below 1800 RPM.

- If the frequency valve duty cycle is not within specifications:

^ Check pre-test requirements.
^ Check the wiring for a short or open circuit.
^ Check the wiring for faulty connections and repair as necessary.

- Turn ignition switch OFF, disconnect tester and test harness.
- Re-connect frequency valve harness connector.