Ive been battling this problem for a while now. My wife habitually topped up the gas tank for years, finally it caught up with us. I do all the work myself since my finances have sucked, but in the past year. Get ready for a long rant
- New Gas Cap x 2
- All new hoses + clamps
- New charcoal canister + vsv's(tax return)
I've checked the vsv under the air filter, its a different type of vsv then what I bought on ebay(thanks fleabay for sucking), haven't replaced those hoses.
Right now im pulling PO440, PO446 and PO446d (don't know what the difference is)
In the process of replacing one part or another the codes have changed somewhat(I believe I had 442 at some point) Even with new vsvs(which work, you can hear them clicking, you can do pressure tests on them), im still pulling p0446
I'll probably/finally get a smoke test done. Recently changed jobs and can actually afford to fix the beast properly. Don't really know what it could be except possibly replacing the FCV fill check valve, aka the onboard recovery valve, which runs 100 ish in parts. Dealer wants 800 to change that out, never done a tank drop so I might get the part/gasket and find a cheaper shop. This part/info was taken from another forum for a celica. It's a valve on the gas tank that I believe feeds into the charcoal canister.
I've searched and read up on the forums many many MANY times.
I don't know if the gas fill tube is leaking or not, I don't smell fuel strongly under the car. But the exhaust doesn't smell right to me.
My gas mileage is horrible, I used to get 300-350miles to a tank. Now I'm at 200-250. (this is a step up, before i changed the charcoal canister i was getting 180. Tires are new and inflated properly. Struts could use a change though.
Also the drive-cycle seems to take forever for me. I live in vegas, lots of short drives. I cleared the code in July, it didn't come back all of august, thinking im good I check the computer, drive cycle still incomplete. Sept 3rd(yesterday) it completed and code is back. We only have one car, i drive my wife two and from work(2miles each eay) Myself to work (8 miles) And do a lot of small trips when shopping.
The Following User Says Thank You to Malakai For This Useful Post:
You have to take care of the first code first, PO440. PO440 means that the Evap is not working correctly. On the '98, the canister VSV purge valve is by the air filter and seldom fails. The one to look at is the VSV for vapor pressure sensor and it is near the canister, under the car. That valve has 3 ports. The other item to look at is the fuel pressure sensor which is plumed to the valve just mentioned. The pressure sensor connector has 3 wires and you should have 4.5-5V between the outer pins with the ignition on. The sensor sends the ECM a voltage on the center pin that is proportional to the fuel pressure. If you Google Corolla PO440 you should find additional information there. Each model year seems to use a different configuration so you'll have to find the one for your car.
I had the exact same situation with the 440-446. Changed everything, still did not work. My mechanic at work kept saying I needed to do a smoke test to see if there was a emissions leak somewhere. My registration fees were getting due and I needed a smog test. I sold the car to him even though he said he would do the smoke test for me. He was busy and said he'd work on it the following week. I decided to sell to him, I bought it for $400 and put another $1000 with tires, brakes, reg fees and other stuff, I made a profit. Anyway, he does the smoke test, he sees a pin hole leak from one of the molded hoses into or out of the charcoal canister filter. A $40 part and he was done. I wish I had another 99 VE. Bought a crashed one, but the chain jumped and will not turn over. Good luck.
You have to take care of the first code first, PO440. PO440 means that the Evap is not working correctly. On the '98, the canister VSV purge valve is by the air filter and seldom fails. The one to look at is the VSV for vapor pressure sensor and it is near the canister, under the car. That valve has 3 ports. The other item to look at is the fuel pressure sensor which is plumed to the valve just mentioned. The pressure sensor connector has 3 wires and you should have 4.5-5V between the outer pins with the ignition on. The sensor sends the ECM a voltage on the center pin that is proportional to the fuel pressure. If you Google Corolla PO440 you should find additional information there. Each model year seems to use a different configuration so you'll have to find the one for your car.
All vsv's have been testing and swapped out with new ones. All hold vacuum. The FPS. Well nothing online says this relates to evap. But for giggles I went out and tested it.
4.7v+ on my 2001
all hoses to and from the charcoal canister are new.
All vsv's have been testing and swapped out with new ones. All hold vacuum. The FPS. Well nothing online says this relates to evap. But for giggles I went out and tested it.
4.7v+ on my 2001
all hoses to and from the charcoal canister are new.
The vapor pressure sensor (fuel pressure sensor in some repair manuals) and VSV for pressure sensor are used to detect faults in the EVAP system and as such part of the EVAP system.
On a 1998 Corolla, VPS operation is tested by back probing the ECM, located behind the stereo on the instrument panel. With the ignition on and the vacuum hose disconnected from the VPS, the voltage between terminals 7 and 9 at the ECM E5 connector s/b 3.0-3.6 volts. Now apply .59 in HG (2 kPa, -30psig) vacuum to the VPS, the voltage at terminals 7 & 9 should drop to 1.2-2.1 volts.
Although not as comprehensive a test, to avoid the hassle of accessing the ECM and still get some indication that the VPS is working, try this. Disconnect the VPS vacuum line and electrical connector. The VPS connector has 3 pins on it. I don't have the exact pin numbering so I'll arbitrarily refer to them as X,Y.Z, with pin X corresponding to the pin location where you previously measured the 4.7V. On the VPS itself measure the resistance between pins Y and X (Ryx) and Y and Z (Ryz). Verify that the sum of these two measurements closely equals the measurement taken between pins X and Z (Rxz). Rxz should be around 2.7 K ohms but that depends on sensor design. Ryz divided by Rxz should be around .67 to .72. Now apply a vacuum of .59 in Hg (2 kPa or -30 psig) to the VPS vacuum port and measure the resistances Ryx, Ryz, Rxz again. Rxz should be the same in both cases, but the ratio of Ryz divided by Rxz should now be around .29 to .42.
Keep in mind that this only tests the VPS and nothing else. If you are still having trouble with your system, the next thing to do is to smoke test it.
Ok Parts needing replacement - Note checking online I can get all items for almost half price.
GASKET, CHECK VALVE Stock Code: 7717702010
CAP ASSY, FUEL TANK Stock Code: 7731048020
VALVE ASSY, FUEL TANK INLET Stock Code: 7739012011
HOSE, FUEL TANK VENT Stock Code: 77404020
Listed at $260 at dealership.
If I buy it myself online I can get it for $120 Shipped
Will see what my mechanic says tomorrow, if he sources parts for fair prices then great.
They also told me that my Crankshaft seal is leaking
Need a new Serp/Drive Belt
Two new tires(They wanted $500 for two tires.....)
and a timing chain Tensioner
Well at least you know where the problem is. My daughter's car has the very same issue. I replaced the VSV for pressure sensor last November and that fixed the problem until summer, at which time PO440 came up. At the time the pressure sensor looked like it was intermittent so I replaced it too but to no avail. Not having a clear picture of the valve function and associated plumbing on the canister, I replaced the canister even though there didn't seem to be anything specifically wrong with it. I'm now waiting to see if the code will come up again, which I suspect it will. For those interested I deconstructed the valves but am not approved to upload document files. I've contacted the administrator for permission.
NOTE: Vapor canisters come as an assembly that includes the VSV for pressure sensor and the pressure sensor. If your canister assembly is old and very rusty, it might be just as well and cheaper to replace the whole assembly rather than any individual parts. The 2 large round pneumatic valves on the canister are not replaceable as separate parts. The valves seal inside is due to the action of a rubber membrane and that too eventually fails. The VSV for pressure sensor is by itself 1/2 the price of the canister, the pressure sensor roughly the same as the canister.
Quick update
Got the parts installed two weeks ago. Drive cycle took forever. Light came back on.
This time codes 440, 441, 442PD, 446.
So I spent all this money just to get more codes.
Brought it back to the dealership today. After another "diagnostic" Which means waiting 5 hours for them to check the car they tell me a purge valve is bad on the charcoal canister......
A purge valve thats already been replaced when I swapped out the canister. Or is this the one under the air box in the engine bay? As per the post above. They want $230 to fix this
Quick update
Got the parts installed two weeks ago. Drive cycle took forever. Light came back on.
This time codes 440, 441, 442PD, 446.
So I spent all this money just to get more codes.
Brought it back to the dealership today. After another "diagnostic" Which means waiting 5 hours for them to check the car they tell me a purge valve is bad on the charcoal canister......
A purge valve thats already been replaced when I swapped out the canister. Or is this the one under the air box in the engine bay? As per the post above. They want $230 to fix this
Yes, the purge valve is in the engine bay. You can check its function by blowing air through it. It is normally closed and opens when 12V is applied.
minor update, So i bought a new purge valve and its the wrong one, (looks like the opposite of what its supposed to be, cant get it into the mount because the bracket would have me install it upside down)
So anyone know the correct part number for this VSV? it's not the same as the one on the charcoal canister
minor update, So i bought a new purge valve and its the wrong one, (looks like the opposite of what its supposed to be, cant get it into the mount because the bracket would have me install it upside down)
So anyone know the correct part number for this VSV? it's not the same as the one on the charcoal canister
After talking to your dealer, you seemed confused about which valve you should replace. There is the EVAP VSV or purge valve which is in the engine compartment near the air filter. This valve has only 2 ports. The vapor pressure sensor (Toyota 89460-12010) is a 2 port device mounted on the canister located under the car near the tank. Then there is the VSV for vapor pressure sensor (Toyota 90910-12267, 184600-3572) which is a 3 port valve that's also mounted on the canister.
I ended up smoke testing the system and found that the gas cap was the problem after all. The seal looked fine but had cracks underneath. Gently lift up the rubber seal around the cap and check for cracks just in case your dealer missed something.
When I replaced the canister on my daughter's car, it came with both a pressure sensor and VSV for pressure sensor. Since I had already replaced the pressure sensor and VSV for pressure sensor just months prior, I now have a spare of each. If you'd like to purchase one or the other then contact me.
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