I have a 2001 LS430. Two weeks ago I received the diag codes, P0440, 0441 and 0446. I lossened and retightened the gas cap and removed the code (via code reader). Now two weeks later, I received the codes again. A number of you found the problem to be the EVAP hose was diconnected behind the cabin air filter. Oh! if i can be so lucky.

I removed the cabin air filter and did not see the evap hose. Additionally, I removed the cover from under the cabin air filter housing area and found no hose under it either.

Does anyone know where the EVAP hose is?


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I'll check Alldata when I get home tonight for you.

I'm battling a P0444 on my Infiniti G35 at the moment.

 

Thanks for the involvement. Look forward to your info.

 

P0440:

The vapor pressure sensor, VSV for canister closed valve (CCV) and VSV for pressure switching valve are used to detect abnormalities in the evaporative emission control system.

The ECM decides whether there is an abnormality in the evaporative emission control system based on the vapor pressure sensor signal.

DTC P0440 is recorded by the ECM when evaporative emissions leak from the components within the dotted line in Fig. 1, or when the vapor pressure sensor malfunctions.

INSPECTION PROCEDURE

HINT:

* If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, first troubleshoot DTC P0441, P0446, P0450 or P0451. If no malfunction is detected, troubleshoot DTC P0440, next.
* Ask the customer whether, after the MIL came on, the customer found the fuel tank cap loose and tightened it. Also ask the customer whether the fuel tank cap was loose when refuelling. If the fuel tank cap was not loose, it was the cause of the DTC. If the fuel tank cap was not loose or if the customer was not sure if it was loose, troubleshoot according to the following procedure.
* Read freeze frame data using LEXUS hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
* When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds , carefully check the vapor pressure sensor.

 

 

I am getting the exact same three codes repeatedly. I cleared them three times before replacing the gas cap. Thought I had it fixed because the codes stayed away for three weeks. But nooo. I got them all back yesterday. They all appear simultaneously. Last freeze frame showed 180F water temp and 685rpm, 0 mph, and 21% calculated load. (plus a bunch of fuel trim numbers.) I'm not sure what to do with all the nice schematics from earlier posts, plus I don't see any resolution. Does anyone have a silver bullet solution or do I need to start random troubleshooting? Direction would be greatly appreciated!

 

Mine was a vapor pressure sensor in the engine bay on my G35. Tested it and it wasn't actuating when given voltage.

 

Thanks for the tip. I'll look at mine. It's frustrating to follow the book and "look for cracks or holes in the fuel tank" etc. Somehow I just don't think that's causing my problem.

 

When i had these codes on my 01, a hose with a green cap (something to do with a fuel vapor return system, located on driver side, under the engine cover) had completely cracked open.

I'd check for any loose hoses. Always a painful process :/

 

that code and symptoms are the same as my UK spec LS, but the code is P10461.


it's the VSV Valve.


mine occured when the engine was over 4k RPM it opens up this valve, when under the 4k RPM it should close again

 

Thank you,

I saw the same three codes and had the exact same problem. For me the hose had just come off from one end.

I will report back if the check engine light comes back.

 

That's a tank side evap code so it shouldn't be anything in the eingine bay. Try replacing the fuel cap with a new O.E. unit from the dealer. The spring in the center go's bad after a number of years. If not that then it's probably the overflow return valve gasket on top of the fuel tank. Though those only go bad usually in hot weather states like arizona and nevada.

 

VSV here too - had to replace it...the valve was completely “dead”.
Part is cheap (maybe around $40) but labour will be a bit more as it is on a nasty spot - hence it takes a few hours to get to it...

 

PARMDHOOT, I did not see anything in the thread confirming your check engine light stayed off, so I assume it did. I am wondering if my issue is identical...I saw an elbow tube which drops vertically and connects to another vertical tube had come off at that end. Reconnected a short while ago...light is still on but I probably have to reset it. Have not had a chance to read any codes. Does this sound familiar? I attach a picture below of the culprit, taken from directly above (birds eye view) so it elbows downward.

Thanks.

 

evap hoses run from the driver side of the engine down the frame rail and on driver side on the frame rail down to the rear where they connect to charcoal canister. Theres no evap hoses in the cabin air filter area behind the glovebox. The evap lines go from the engine to the rear outside of the car. Remove the Engine Cover and look on top of intake should be 2 lines that run across the driver side valve cover. there should be a green cap that looks like a valve stem. that is a test port for smoke testing the system.