B. Inspect the "to Tank" Circuit

1. Locate the hose between the canister close valve and the fresh air filter. Slide the hose clamp back and disconnect the hose at the air filter.

2. Insert one end of the "test" hose, about four inches, into the fresh air hose at the canister close valve.

3. Slide a hose clamp over the two hoses.





4. Place the HDS in "DIGITAL RECORD" mode. While watching the DPS signal on HDS, GENTLY begin to blow into the "test" hose (the DPS voltage should begin to rise). Continue to gently blow into the hose until the DPS voltage is approximately 4.0 volts. Do not over pressurize since the sensor cannot read over 4.5 volts.

5. a. Apply hose pinching pliers on the "test" hose. The DPS should read a constant value at this point (if the value does not remain constant +/- 0.05 volts over 10 seconds; refer to "P0455/P0442 Leaks" section and then return to finish this inspection).

b. Remove the hose pinching pliers from the test hose. The system should return to atmospheric pressure in approximately 45 seconds. If it takes longer than 45 seconds, move the "test" hose to the front of the fuel tank and repeat the procedure checking for restricted vapor hoses or internal blockages in the "To Tank" circuit. If the system returned to atmospheric pressure within 45 seconds, then proceed to Part C.

6. Use the "Pressurize/Clamp/Observe" method to isolate the blockage closer each time to the DPS sensor.