EGR Backpressure Transducer: Testing and Inspection

Two Port
1. Disconnect both vacuum hoses from modulator.
2. With engine stopped, block either port of modulator and blow through remaining port.
3. Air should be discharged from modulator filter with little resistance.
4. Start engine and set to run at speed specified under ``System Testing,'' block either port of modulator and blow through remaining port.
5. Air should be discharged through modulator filter with great resistance.
6. If valve fails to perform as outlined, valve is defective.

Three Port
1. Disconnect vacuum hoses from EGR vacuum modulator.
2. Place finger over the two end ports.
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 3000 RPM.
6. Repeat test and ensure there is a strong resistance to air flow.