D. Evaporative Emissions Self Check Must Be Performed

D. The evaporative emissions self check must be performed to ensure system integrity.

II. P0441 is in the PCM memory, perform the following procedures:

A. Inspect the "Purge" Circuit

1. Remove the canister purge valve and blow through it in both directions. The valve should not allow air to pass through it without it being energized. Replace the valve if necessary.

2. Reconnect the canister purge valve and perform the self check. Note:This purge circuit check will only confirm an engine vacuum leak, not a leak to atmosphere. To detect atmospheric leaks, see "P0455/P0442 Leaks" for the troubleshooting procedures.








III. P0455 is in the PCM Memory. This can be seen on the HDS self check as a slow response in DPS voltage during the large leak check. Within 5 seconds after the purge control valve begins to cycle, the vacuum must be drawn down 0.04 volts (see graph 4). Within 9 seconds after the purge control valve begins to cycle, the vacuum must drop more than 0.64 volts from atmospheric pressure (see graph 5). If the system does not draw down to the voltages described above, there may be a large leak or a restricted hose in the system. To inspect system for a large leak, see "P0455/P0442 Leaks" for the troubleshooting procedures.





IV. P0442 is in the PCM memory. This condition can be seen on HDS as a rise in voltage of over 0.17 volts during the small leak check (see Graph # 6). To verify the rise in voltage from the self check, use the digital overlay as described earlier. Use the track ball to place the cursor at the point when the canister close valve opens the second time. Click on the left side of the vertical line (note the voltage value of the DPS) and then move the cursor to the left until the bottom of the screen reads 5 seconds. Compare the two voltage values and the increase should be less than 0.17 volts. To inspect system for a small leak, see "P0455/P0442 Leaks" for the troubleshooting procedures.