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AbyssalCreation 08-25-2011 09:41 PM

01 IS300 with a p0440 (pic)
So last week my CEL popped on and my mood was instantly ruined. Went to autozone and they tell me that it was showing a p0440 code. Something in the EVAP system. Ive searched through the forum for a couple days now and its driving me crazy. I have a tech friend at a lexus dealership intown telling me that its most likely a valve that located on top of the fuel tank. He also told me the only way to get to it is lower the tank which is a bit of a hassle. I had another friend call it a roll over valve.

I did check this valve today and it seem to look fine.
I think its part of the VSV system and i have a stock airbox.

Is this job possibly a diy if the carbon canister is removed? This really sucks because i have a smog due in a week.:confused:

1SWEETLEXUS 08-28-2011 12:19 AM

Do you smell gas? No? then you might just need to tighten your gas cap. Do that and reset the code...

AbyssalCreation 09-01-2011 12:36 AM

Filled the gas up to the 3/4 mark and didnt let it drop past the 1/4 mark after i reset the ECU. Drove about 150 miles and made sure the gas cap was on tight at all times and the CEL came back on. Gonna go to autozone tommorow and see if its the same code and then face my doom at the smog place. Hopefully the dmv gives me some time to get it fixed. Ill update tommorow with tears-a-flowin'.

jasonm4 09-01-2011 05:37 AM

P0440 is same as P0441, which is detection of a lack of negative pressure in the system/(tank) and tells you to check the same things pretty much as DTC P0446. The purge/vent sensor is used to detect abnormalities in the EVAP system(charcoal canister). Signal from that sensor tells ECU that the purge VSV pressure within the CC needs regulated. If ECU senses no change, a DTC is set. I would check by the brake booster and make sure you have no leaks there, as well as up by where the stock airbox sits. The CC VSV is there, but make sure the line(tubing) running into it from the rear is hooked up to it. When both of these codes are thrown, diagnostic states this is a large leak. Sometimes these codes are thrown if the tank is overfilled a few times and the over fill check valve would become cracked or damaged. I'm betting you have a VSV stuck or a line is open/not in vacuum.

P0440 Evaporative Emisson Control Sys Malfunction: The ECM has detected abnormalities
in the evaporative emission control sys for the vapor pressure sensor and VSV for vapor sensor caused by loose gas cap
Check for:
Cracked, holed, damage or loose hose or tube.
Fuel tank cap not installed properly.
Fuel tank cap cracked or damage.
Fuel tank cracked, holed or damage.
Vacuum hose cracked, holed, damage, blocked or disconnected.
Charcoal canister cracked, holed or damage.
Open or short in the vapor pressure sensor circuit.
Vapor pressure sensor faulty.
Fuel tank over fill check valve damage. ECM.

jasonm4 09-01-2011 10:29 AM

Also, as I mentioned above, the CC VSV will give you code P0440 because I forgot to hook it back up the stock air box one time long ago. Worth checking out.

AbyssalCreation 09-01-2011 05:27 PM

Is the CC VSV the same check valve that i took a picture of in my original post. It seemed to look fine to me.

jasonm4 09-01-2011 05:44 PM


Originally Posted by AbyssalCreation (Post 6490111)
Is the CC VSV the same check valve that i took a picture of in my original post. It seemed to look fine to me.

Ah, yes, you're correct. That VSV looks okay to me but it's hard to say what might be the culprit as there is a long list of EVAP errors that would give you P0440. Usually it means the gas cap or a leak in the system. High lead content in fuel can even set this code.

MR. M 09-01-2011 06:02 PM

Ive had the same code (p0440) for the past few weeks never able to find a direct answer to tackle the problem, ive done some research, changed the gas cap didnt overfill and the best thing i found to do was a smoke test hopefully which i will be doing soon. If you figure something out let me know

AbyssalCreation 09-01-2011 10:46 PM

Well i failed my smog today. :cool: Im gonna hit the DMV tommorow and get some sort of temporary moving permit then go to the stealership and get a new gas cap and a Rollover valve/overfill valve. Only way to get to the valve is to drop the entire gas tank.

Or not.... find out what happens in my next post. muhahaha.

AbyssalCreation 09-21-2011 06:55 PM

I thought i would report back about the car. Check engine light is gone, its been smogged and registered as well :-)

To summarize what happened... My car was throwing p0440 code which has something to do with the EVAP system. The car wasnt able to pass smog with this code so i asked around and a few friends that work at the lexus dealership in town suggest changing the rollover valve which is located above the fuel tank.

Upon further investigation i found that lexus doesnt call it the "Rollover Valve" but instead they call it a "Fuel Tank Overfill Check Valve." The fuel tank needs to be dropped to get to the part per the service manual. I had some estimates on how much the dealer would charge and it came to around $700.

I was looking at the blueprint for the fuel tank and found exactly where the valve is located and basically its off to passenger side of the hump under the back seat. The bottom of the backseat needed to be removed just like when youre doing a fuel pump. I sawzalled a hole big enough to get to the part, not a complete hole but just enough to flap open. I replaced it and put sound deadener on top of the hole. I would not suggest doing it this way since i did come really close to cutting a rubber fuel line, so please dont be a noob like me. I know its ghetto but i was on a deadline and wanted to get the car on the road immediately for the least amount of money possible. Interior noise hasn't increased whatsoever if anyone is wondering.

Im really glad to say all is well with the car now and i only used oem parts from the dealer. Decided to change the gas cap as well since the car has 210k miles.

Heres the part #'s just in case someone needs them.

7739053010 - Fuel tank overfill check valve

7717712020 - Gasket for overfill check valve

7730008010 - Gas cap!

dakinISbatman 09-21-2011 07:17 PM

Well, at least you got it done. but i must say OUCH!

AbyssalCreation 09-21-2011 07:35 PM

if i had a pristine IS with low miles i wouldve done it the right way but unfortunately i don't. The previous owner didn't give a shit about this car but im trying to improve it!

akcentu 01-11-2012 04:50 PM

worked for me p0440 gone

che's300 01-11-2012 05:20 PM

is cutting a hole really nessesary? that looks horrible.

jasonm4 01-11-2012 05:31 PM

So, you used a sawzall to cut open your gas tank to replace the roll over check valve? Surely I hope the tank was empty if so. Fuel vapors and sparks is a bad situation, even though you were using water to prevent any sparks.

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