P0411 and Gas Mileage???
#11
01-09-2010, 04:12 PM
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the pcm operates the evap vapor purge process every once in awhile. that's a cycle. i don't know if it does it at every startup, or every so often on time, or every so often on mileage. but when it does, it uses sucks the evaporated gasoline out of the charcoal cannister and into the intake where it can be burned. it somehow monitors the success of this process by measuring pressure or vacuum or something.
i noticed that when i had my p0441 going on, after resetting the pcm it took 2-3 days for the cel to come back on. so the pcm either had a long delay between purge cycles, or a tolerance for failure before it set the CEL.
http://www.autoshop101.com/forms/h62.pdf
by design, the pcm contains some capacitors that hold power to the pcm memory, so that you can change a battery and not lose stored codes or adaptive (big word) memory. if you leave the battery disconnected long enough (an hour?), those capacitors will drain on their own. if you turn on the headlights, or turn the ignition to start, then the increased short to ground will drain the capacitors within about 30 secs. this is referred to as resetting the pcm.
i noticed that when i had my p0441 going on, after resetting the pcm it took 2-3 days for the cel to come back on. so the pcm either had a long delay between purge cycles, or a tolerance for failure before it set the CEL.
http://www.autoshop101.com/forms/h62.pdf
by design, the pcm contains some capacitors that hold power to the pcm memory, so that you can change a battery and not lose stored codes or adaptive (big word) memory. if you leave the battery disconnected long enough (an hour?), those capacitors will drain on their own. if you turn on the headlights, or turn the ignition to start, then the increased short to ground will drain the capacitors within about 30 secs. this is referred to as resetting the pcm.
#13
01-09-2010, 04:20 PM
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#14
01-09-2010, 04:48 PM
i use to live in Maine, id go camping with my dad (he drove a 96 ram 1500 5.2 2wd) and when we started climbing, she kept downshifting/boggin, when we went down the other side, CEL always popped on and she'd run fine....first time it happened he looked at me and goes, "that was nothin, always does it,.. is it my hit?" lol, and then thats how i learned of the elevation thing....he just would unhook the battery when we got there, and hook it back up 5 mins later with no more CEL....then it was time to get beer...
#15
01-09-2010, 05:25 PM
The '97 Ram did not do evaperative system leak detection so you can leave the gas cap off and it doesn't care. The P0441 code means the computor does not see the purge system working. The solinoid is not working, no vacumn to the solinoid, canister disconnected, etc. The computor energizes the purge solinoid and looks for O2 sensor response, if it see's nothing, you get the code. You could have real slow responding O2 sensors, that would make the lamp more intermitent
#16
01-09-2010, 05:39 PM
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#17
01-09-2010, 06:09 PM
Evaperative emission leak testing started in the '98 model year so that year and newer, leaving the gas cap loose causes a leak and sets a code. The '97 has no leak testing so leaving the gas cap off does nothing but create a fire hazzard. If your getting a P0441 in that year it's because the purge system isn't working.
#18
01-09-2010, 07:31 PM
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#19
01-09-2010, 08:42 PM
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Evaperative emission leak testing started in the '98 model year so that year and newer, leaving the gas cap loose causes a leak and sets a code. The '97 has no leak testing so leaving the gas cap off does nothing but create a fire hazzard. If your getting a P0441 in that year it's because the purge system isn't working.
#20
01-09-2010, 08:45 PM
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Evaperative emission leak testing started in the '98 model year so that year and newer, leaving the gas cap loose causes a leak and sets a code. The '97 has no leak testing so leaving the gas cap off does nothing but create a fire hazzard. If your getting a P0441 in that year it's because the purge system isn't working.
This is what I don't understand..... if my "system" is broken why doesn't the check light come right back on immediately ..... after I reset it by disconnecting the negative battery cable.... ???
In other words the light doesn't come on for thousands of miles and then decides that the purge systems isn't working... Sorry but I'm sort of groping for words...... LOL