EGR Backpressure Transducer: Testing and Inspection

Fig. 9a EGR Vacuum Modulator Filter:

Fig. 178 Testing EGR Vacuum Modulator Air Flow:

1. Check the filters in the top cap of the EGR vacuum modulator for contamination and damage. Fig. 9a
2. Using compressed air, clean the filters and reinstall.
3. Disconnect the vacuum hoses from ports P, Q and R of the EGR vacuum modulator.
4. Block ports P and R with your finger.
5. Blow air into port Q and check that air passes through to the air filter side without resistance. Fig. 178
6. Start the engine and raise speed to 2,500 rpm.

Fig. 179 Testing EGR Vacuum Modulator No Air Flow:

7. Repeat steps No. 4 and 5 above. Check that there is strong resistance to air flow on air filter side. Fig. 179
8. If a problem is found, replace the EGR vacuum modulator.
9. Reconnect the vacuum hoses to their proper locations.