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It can be a gas cap, low amount of gasoline in tank or the charcoal canister among other things. I got one of those a few months ago. Disconnected the battery and all was well afterwards.
Do a search and you'll find that the system sometimes send P0440 Evap system codes for no reason, not necessarily a fault. Make sure the air filter housing and respective vaccum hoses are all properly connected and reset the code, I reset mine 1 year ago and never came back.
The link you provided had 3 codes in it 440,441 and 446.
His problem was probably a bad Vsv at the canister side.
The OP has only the 440 code which is a leak detected in the fuel tank side.
P0440
After cold starting and when generating certain swift pressure
valve in fuel tank enabling not to hold that valve (2 trip detection
logic)
Fuel tank cap incorrectly installed
Fuel tank cap cracked or damaged
Vacuum hose cracked, holed, blocked, damaged or disconnected
((1) or (2) in Fig. 1)
Fuel tank cracked, holed or damaged
Charcoal canister cracked, holed or damaged
Open or short in vapor pressure sensor circuit
Vapor pressure sensor
Fuel tank over fill check valve cracked or damaged
^^As you can see the first 2 possibilities lies in the gas cap.
He could have other problems but the simplest way to find out is check his Gas cap condition first.
Check the vacum hoses on air filter unit, terrible design function. So I just bought mt '02 RX300 last month with 101,000 miles on it in near perfect condition; one owner, grandma, all dealer maintained, all records = SCORE! However, after putting 4,000 mile on it in a month and a half I chose to get an oil change and tire rotation at Pep Boys in Lodi, CA for $24.99... Great deal and an oil change, any monkey can do that... Right? WRONG!!! After calling ahead to see if they could get it done in an hour, and getting assured that they could, I went down to get it done. After an hour and a half they came out to say that they were having trouble getting the filter out. Then after two hours they said all was done and I was ready to go. Two days later, my check engine light and VSC light came on, and needless to say I was upset after only making one payment so far. PB's offers free code reading so I took it in to get it read, codes came up P0040, P0046, and my VSC. PB said they then needed 150.00 to diagnose the issue, but having the codes I decided to take codes and do research myself and take it to the dealer if needed, as my confidence in PB was pretty low. After a google search I saw that someone else had this problem, and checked the air hoses under the car by the Charcoal Box, and no issue. Then I check the Air Filter box under the hood and sure enough, there was a hose on the back of the box that connected to another hose that runs under the car to the Charcoal Box... UNCONNECTED. Thats it, reconnect the damn hose and disconnect the negative terminal on the battery and ALL the codes are gone and gas mileage is back to +24mpg... Moral of the story... Do your homework before you pay.
I hope this helps save someone $$$ and stress. Fixed in 5 minutes work and 30 minute reset time.
^^^
Ditto.
The Tread Quarters coupon I had was too good to pass up.
I can't even buy oil and a filter for that price.
Of course they want to see if they can sell me an air filter and the hose in the back comes loose.
Next day the dash is lit up like a Christmas tree.
This time, my 2000 RX300 was throwing only the P0440. After much research and looking for leaks, I stumbled onto my leak(s) while messing around with the Evap unit under the rear. All the Evap hoses were in good visible condition.
A couple days later, after finding no apparent hose problems under the hood, I went back to the rear to follow the hoses to their destinations. I started pulling on Evap hoses and noticed that two of the thicker hoses (they're about 6 or 8" long) were not quite as tight on the Evap nipples as the smaller ones were. The thicker hoses seemed tight enough to me for push on vacuum hoses. They run from the Evap unit to some pipes that look like black plastic coated steel, or black painted steel.
Then I thought, "What if these are push on pressure hoses? If they are, they aren't tight enough for my taste." So I drive down to the parts house, threw a towel on the pavement, crawed under the rear and pull off those two hoses. They didn't have any gas-resistant vacuum hose, but they did have some 5/16" (I think it was) fuel line hose. I took a piece of that outside to test fit and it was a really tight fit, but I was able to get it over the steel pipes. I put the old hoses back on, bought the whole 3ft piece they had as a courtesy and to have some extra on the shelf, and went home. There I pulled of the old ones again and cut the new hoses to size. Thankfully that 5/16" hose went on the plastic Evap nipples with no problem, but it it took some spit to get them shoved on the steel tubing about a half an inch (btw, I still don't know where those steel hoses lead to).
I immediately used my Android "Torque" app and (authentic) ODBII code reader ( http://www.totalcardiagnostics.com/elm327/ ) to reset the codes and turn off the Check Engine Light. Before replacing the hoses, the Check light would come on in about 3-5 miles. This time, that passed and I waited to se if it would pass the 50 mile test . . . . BINGO! Problem Solved! :
It's been about 100 miles since and I'm calling this one fixed :-)
Here's a pic of those hoses. Sorry I didn't think to take a pic with the new hose on : Note the red line on the subject hoses:
Btw, there was huge solid mud "mud dabber wasp" nest on top of that upper round thing (I marked with a green line). Fortunately for me, the mud dabbers were on vacation, so I knocked it out of there. If anyone wants to name the parts I can't identify in this post, please do.
Btw, I leave that ODBII reader plugged into the diagnostic port all the time. It was very handy to turn off the CE light so I'd know if a more serious engine problem developed when the light came on. Only problem leaving it installed is that people who are not aware of it, think it's an emergency brake pedal to be pushed on. A family member tried that, but somehow managed not to break anything.
Looking at the Vacuum diagram under the hood, the hoses I marked with red are the "To <evap> Canister" and "From <evap> Canister" lines. Here the label from under the hood:
Just for the record, where it shows "Vacuum Tank". Anyone have a picture of where that's located? I couldn't find it or didn't recognize what I was looking at.
Nice writeup. Couldn't you have used hose clamps if the hoses were not air tight?
Vacuum tank is under the battery against the driver side fender.
100 miles is probably enough but there are complex series of conditions that you have to get past before the the monitor passes the readiness check. I haven't used the torque app but it should be able to tell you if all emission readiness checks are done.
Humm . . . since the rubber on those two hoses looked ok (had some minor checking on the ends), I suppose I could have trimmed of 1/8" and clamped them. I didn't even think about it. Duh . . . weekend mechanic. Good suggestion for someone without the extra new 5/16" fuel line on the shelf (just give the hoses the suck test for unseen leaks).
I'm keeping my fingers crossed: It's been 106 "around town" miles (no freeway/turnpike yet).
Thanks for the kudos on the write-up. Especially thanks for the pointing me to the vacuum tank.
02-15-10, 07:55 AM
rx300 code P0440 what do I check?
