After buying the " Autoenginuity Scantool" (loving it) and having cleared code: (Vechile Speed Idle Control - P440 - Evaporative Emmission Control System) four times in the last two months perhaps it is time to find out why it keeps coming back!!! The code disappears for days or even weeks after being cleared. I'm wondering if it has something to do my check gas cap that I have had problems with since I bought the car. I have tried every trick mentioned on this website to get rid of the problem. Including having the dealer install a new gas cap, smoke test on evap system, pressure test on system, and cleaned the filler neck to ensure sealing was taking place. The P 440 code did show up on the dealers work order when I had the above problem checked so that is why I wonder if there is a connection? Any suggestions would be greatly appreciated. [/code]
Electrically closing the vent valve in order to seal the system.
Electrically opening the purge valve which allows the running engine to draw a vacuum on the fuel tank.
The pcm then closes the purge valve, resealing the system.
The pcm then monitors the fuel tank pressure sensor and determines:
;If vacuum was achieved.
;If a leak is present, how large the leak is.
;If vacuum was not achieved.
If one of the above tests fails, the pcm remembers that the system failed the test.
If the pcm sees a failure of the EVAP test for two consecutive tests, the module will set a trouble code for EVAP leak (DTCs P0440, P0442, or P0446).
Banned for crimes against the Forum
There are a lot of parts that make the evap system and they sure are a pain. You have the new cap and have run several tests with the dealer, it comes and goes about twice a month.
Does the code show up after you fill up or soon after?
Might be a sticky purge valve, or vent valve?
Do you get any other codes or just the 440?
For the last few days I have been reading manuals on this evap system and all the quirks that can go wrong. I'm amazed other than check gas cap message, after 108,000 miles on my 2k that I have not had a problem. And I still have the original cap
There is a charcol filter for the gas fumes, if this gets saturated with gas, and this can happen when you over fill, you can set an evap dtc if the car is started twice with this condition.
I do believe my next purchase will be a shop manual. Has anyone used the computer online version of the manual such as ALL DATA for $29.00 a year. Makes sense if it is any good. By the time I pay for a written shop manual hopefully I've upgraded to newer model.