EGR Backpressure Transducer: Testing and Inspection

Fig. 9a EGR Vacuum Modulator Filter:

1. Remove the top cap from the EGR vacuum modulator and remove the air filters. Fig. 9a
2. Check the filters for contamination or damage. Replace if necessary.
3. Reinstall the filters and the top cap.

Fig. 55 Testing EGR Vacuum Modulator Air Flow:

Fig. 56 Testing EGR Vacuum Modulator No Air Flow:

4. Disconnect the vacuum hoses from ports P, Q and R of the EGR vacuum modulator.
5. Block ports P and R with your finger, while blowing air into port Q. Fig. 55
6. Check that air passes through air filter side freely.
7. Start the engine and maintain speed at 2,000 rpm.
7. Repeat step 5. There should be strong resistance to air flow through the air filter side. Fig. 56
8. If a problem is found, replace the vacuum modulator.
9. Reconnect the vacuum hoses to their proper locations.