EGR Vacuum Modulator

Fig. 21 Vacuum Modulator Test (Engine Stoped):

Fig. 22 Vacuum Modulator Test (Engine At 3,000 RPM):

1. Disconnect vacuum hoses from EGR vacuum modulator.
2. Place finger over the two end ports, Fig. 21
3. Blow air into the single port.
4. Ensure air passes through the air filter side freely.
5. Start the engine and maintain engine speed at 3,000 RPM.
6. Repeat test and ensure there is a strong resistance to air flow, Fig. 22