[theraflu]

https://www.ebay.com/itm/33211320402

I don’t have the other valve PN on hand. The vapor valve will have a hairline crack on the top section. Hard to believe that it cause the code but it does.
When you smoke test it you might see smoke on the RR top side of the tank. Plus real diagnostic smoke machines produce a peculiar smell, you’ll recognize it.

 

[CWilder]

So, I have not looked at the charcoal canister, VSV, or the check/vapor valve on the gas tank.

VSV - Amazon.com: Genuine Toyota Parts - Valve Assy, Vacuum S (25860-46010): Automotive

Check Valve - Amazon.com: Toyota 77390-53010 Fuel Tank Over Fill Check Valve Assembly: Automotive

 

[CWilder]

I found one more "cracked" vacuum hose. Replaced and clamped. Reset the check engine light

 

[andrewkpt423]

I found one more "cracked" vacuum hose. Replaced and clamped. Reset the check engine light

report back with results please. everyone finds something but never says the issue or results after fixing THE MOST common problem with these cars.

 

[CWilder]

report back with results please. everyone finds something but never says the issue or results after fixing THE MOST common problem with these cars.

Most common HAS to be #2 control arm bushings.... inner tyre wear...LOL

 

[CWilder]

Light back on with same codes after approx 500 miles. I got the smoker, where should I tap in to check 1st?

 

[01 SolarYellow]

Look in the factory manual for the procedure. You must bock of one connection.

 

[CWilder]

I did not see what I was looking for here

 

[ill_mannered]

On that evap solenoid that is located on the back of the intake manifold there is the small u shaped hose that normally cracks on these. Anyway on that valve there should be two hoses attached to it. The U-shaped hose should run into the intake (where the fuel vapor will be allowed enter back into the engine).

there will be another hose on top of that same valve. Follow that hose back and there should be a EVAP service port. This is where you can hook your smoke tester up to. Disconnect that top hose from the valve. Then clamp that end shut tight. Hook up the smoke tester and pump in smoke and look for leaks. This should flow through the entire system.


Here are two links:

https://www.clublexus.com/forums/attachments/is-1st-gen-2001-2005/410418d1496511828-engine-air-and-evap-hose-diagram-evap.pdf

https://www.clublexus.com/forums/attachments/is-1st-gen-2001-2005/410419d1496511828-engine-air-and-evap-hose-diagram-evap2.pdf

 

[2JZ-duz-it]

After trying the gas cap, I fixed my P0440 by cutting the sheet metal under the seats and replacing the fuel Overfill check valve on top of the gas tank. It's tons easier than dropping the tank. I do not recommend using a saw or anything that produces sparks. I used metal shears and as soon as I pryed open the panel the car was fuming with the smell of gas. Whole process took maybe 40min tops.

 

[CWilder]

After trying the gas cap, I fixed my P0440 by cutting the sheet metal under the seats and replacing the fuel Overfill check valve on top of the gas tank. It's tons easier than dropping the tank. I do not recommend using a saw or anything that produces sparks. I used metal shears and as soon as I pryed open the panel the car was fuming with the smell of gas. Whole process took maybe 40min tops.

Yea, I went ahead and ordered it because I have yet to hear a high mileage IS that has not needed this done. Thanks

LEXUS OEM FACTORY FUEL TANK OVER FILL CHECK VALVE AND GASKET 2001-2005 IS300 | eBay

2001-2005 IS300. LEXUS OEM FACTORY FUEL TANK OVER FILL CHECK VALVE AND GASKET. WE ARE A LEXUS DEALER SO WE CAN HELP YOU WITH ANY OF YOUR LEXUS NEEDS. THIS PART IS NEW AND BEING SOLD BY AN AUTHORIZED LEXUS DEALER.

www.ebay.com

 

[CWilder]

Well, I need to get this evap leak fixed...

 

[CWilder]

So I have parts for the check valve on the tank and the VSC at the canister. I did not realize there were 3 VSVs in the system. Thought there were just 2...

 

[CWilder]

So I decided to smoke the system, but I could not find a leak. Found my smoker was blowing smoke and drops of mineral oil back toward the canaster so I used shop air and blew in all our from charcoal canaster side back to front. I used a pure baby mineral oil from Walmart … it was all they had... smelled baby fresh too.

Next, decided NOT to drop the tank as I was certain I could not do it in one day and disturbing so much on my car with almost 280K miles made me nervous. So I cheated and removed the back seat and swapped the check valve/ roll over valve. I put an air purge on the top side of the tank from underneath and used a Dremel to cut a lip open in the sheet metal above the check valve under the rear passenger side seat. I removed the check valve and gasket and they did not look damaged at all, no hairline damage or anything. I could not smell ANY gas until I removed it from the tank. I decided while I had the charcoal canaster cover off to replace all the hoses to the canaster too. I really don't know if anything I did helped the P0440 code or not. I used JB weld to seal the sheet metal back into position and will put the rear seat back in in the morning.

Guys, I don't know if I really needed to replace the check valve on the tank. Oh well, there is a new one there now...haha

I reset the code and will see if it comes back now. Let me know if you have any thoughts

 

[ill_mannered]

Did you pump smoke into the evap service port as shown in that diagram? With everything else shut tight?

 

[CWilder]

I did not have an adaptor for the port, so i just disconnected the hose and smoked the system going to the canister.

 

[CWilder]

Ok guys, after 300 miles, the P0442 (Evap Emissions System Leak Detected (small leak)) returned. No P0440 right now. Hoping the check valve resolved that one.

Not sure where to try next? Did not have a lot of success with the smoke tester that I purchased.

 

[01 SolarYellow]

Only thing left would be to inspect every inch of the rubber and hard lines.

 

[CWilder]

I was planning to do everything I could without dropping the tank... with the age of this car, think I would be breaking alot just to get this tank down. It might be down for a week while I find parts too. This has been my daily driver...

 

[ill_mannered]

Hmm. Maybe you can give the smoke tester another go? And check every possible hose in the engine bay, jack the car up and look for any smoke around the gas tank and fuel filler neck?

I know you tried it already but maybe there might be hope yet lol.