Evap emissions and a mysterious black box, haynes has no idea what this thing is Options

[enderswift]

hey 6gc,

I have a question for your collective hive mind of wisdom. I'm trying to diagnose an evap emissions code and cant figure out what this wierd black box is behind my fuel tank. Haynes is useless since it doesn't even show it anywhere in the fuel system diagrams. I'm really stumped by this!

here are the pics:



its located in the space between the fuel tank and the spare tire well




it has a bunch of what look like solenoids connected to it. not only that it seems as though the fuel send and return lines are involved as well, but im not sure as i havent dropped the tank

anyone know what this is? what it does? and how it can break/influence evap codes?

[Bitter]

looks like a charcoal canister, you have a gt correct? looks like what came on a camry of the same vintage.

[enderswift]

i think you're looking at the cylinder dealie. I'm talking about the huge box in the picture. a friend of mine said it could be a vacuum box?
.

[Stambo]

yup thats a charcoal canister thats where you'll get a small evap leak sometimes from the vent solenoid

[enderswift]

really? okay, so the celica has two charcoal canisters? a cylinder shaped one in the engine bay, and a rectangular one behind the gas tank? does anyone have a repair manual that actually details the evap system? cuz haynes really sucks

[enderswift]

ahh the cylinder that i thought was the charcoal canister in the engine bay is the fuel filter! silly me i was sooo convinced that the charcoal canister and purge valves should be at the front like my old car!
ok so the charcoal canister is in the back. Where its controlled by the VSV, since this is a '99 and the switched from tvv in ~'95.

so is there a common problem with the evap system that i should know about?

[Stambo]

not unless you get a code for a evap leak, you really have nothing to worry about. Sometimes tho the vent solenoid gets stuck and leaks.

[enderswift]

yea i have a evap code. sigh, its driving me nuts. Its really wierd that the charcoal canister is in the back of the car when all of the manuals say it should be up front together with the vsv. I guess Toyota switched to an updated system in '99 or something. im going to take that whole section apart to see whats going on with that leak since all the lines seem to be in good shape

This post has been edited by enderswift: Mar 26, 2010 - 10:16 AM

[Stambo]

if you could get ahold of a smoke machine you'd be in business

This post has been edited by Stambo: Mar 26, 2010 - 1:43 PM

[DGAF]

What evap code are you referring to? There is several and it woul point out where to start looking!

And yes, That is a charcoal canister, and no. Probably your problem will be a little further up front. The solenoids that control vacuum for the evap sell a lot on toyota engines. But you know where to look when you get the exact code.

Good Luck!!!!

[Bitter]

not uncommon for the evap valve on the canister to go bad since its the most exposed to the elements under the car there. usually you replace the canister with the valve because a common failure is for the charcoal to get loose and clog the valve or stick it open/closed. also they just fail where they don't open anymore but ohms test fine.

[enderswift]

thanks for the responses guys,

I looked into it and it turns out that 98-99 celicas share the same updated evap system as the 5sfe camry's. So a quick search for camry evap issues shed light on all the things that junk haynes manual wouldn't cover.

heres the break down for those who may run into the same issue in the future:

the 98-99 celicas have a large rectangular charcoal canister located in the rear of the car - right between the gas tank and spare wheel well -
attached to this tank are two cylindrical valves which are controlled by the vsv (vacuum solenoid valve) which is also in the rear of the car (keep in mind that our cars have two vsv's, one in the front for the egr and one in the back for the evap). The vsv is the main vacuum junction that controls when the charcoal canister draws fumes from the tank and when it sends those fumes to the intake manifold via those two cylindrical valves i mentioned. Apparently, the design of the vsv causes it to fail quite often and the fact that its located right underneath the car means its exposed to some harsh conditions that expedite the failure.

when the thing breaks (as it inevitably does) it will trip one of two codes which may or may not cause an intermittent check engine light.

The first code is P0441 which says there is a flow fault. this code could mean any number of things ranging from loose gas cap to leaks in the lines, or even a cracked charcoal canister. AKA this code doesn't tell you jack sh*t other than something is broken with the evap.

the other more telling code is P0446 evap circuit fault. This one points directly at the VSV or any connections leading up to it. *keep in mind that a bad vsv can trigger either code or both at the same time (intermittently), which makes diagnosing the exact issue a little problematic. obd II ftw...

so how to solve the issue? well if you have a basic understanding of how a solenoid works you will understand that the steel plunger within the coil can get stuck from corrosion, keeping it from moving. This is when the vsv is stuck open or closed thus causing the cel. A good rule of thumb with solenoids is that a good whack can temporarily free up the shaft until a replacement can be installed.

thats exactly what i did. first i connected a 12 source to the vsv to see if it would click. it didn't. so i took a screw driver and a hammer and whacked the bracket that was holding the solenoid. When i reconnected the power it clicked just fine. The check engine light hasn't come on since

hope this helps someone in the future

oh and one more thing.
<-----what the hell does a guy have to do to get a third square around here? im not about to turn into a spam whore but god damn its been forever haha

This post has been edited by enderswift: Mar 27, 2010 - 7:14 PM

[Smaay]

im gonna bump this thread just for those considering a V6 swap. this is the newer cannister which will make it easier to do this swap and have the EVAP work. i have a 97 and right now wish i had a 98 or 99. but if the gas tanks are the same i might be able to squeeze this cannister up in there

[DIONYZUZ]

thanks for the responses guys,

I looked into it and it turns out that 98-99 celicas share the same updated evap system as the 5sfe camry's. So a quick search for camry evap issues shed light on all the things that junk haynes manual wouldn't cover.

heres the break down for those who may run into the same issue in the future:

the 98-99 celicas have a large rectangular charcoal canister located in the rear of the car - right between the gas tank and spare wheel well -
attached to this tank are two cylindrical valves which are controlled by the vsv (vacuum solenoid valve) which is also in the rear of the car (keep in mind that our cars have two vsv's, one in the front for the egr and one in the back for the evap). The vsv is the main vacuum junction that controls when the charcoal canister draws fumes from the tank and when it sends those fumes to the intake manifold via those two cylindrical valves i mentioned. Apparently, the design of the vsv causes it to fail quite often and the fact that its located right underneath the car means its exposed to some harsh conditions that expedite the failure.

when the thing breaks (as it inevitably does) it will trip one of two codes which may or may not cause an intermittent check engine light.

The first code is P0441 which says there is a flow fault. this code could mean any number of things ranging from loose gas cap to leaks in the lines, or even a cracked charcoal canister. AKA this code doesn't tell you jack sh*t other than something is broken with the evap.

the other more telling code is P0446 evap circuit fault. This one points directly at the VSV or any connections leading up to it. *keep in mind that a bad vsv can trigger either code or both at the same time (intermittently), which makes diagnosing the exact issue a little problematic. obd II ftw...

so how to solve the issue? well if you have a basic understanding of how a solenoid works you will understand that the steel plunger within the coil can get stuck from corrosion, keeping it from moving. This is when the vsv is stuck open or closed thus causing the cel. A good rule of thumb with solenoids is that a good whack can temporarily free up the shaft until a replacement can be installed.

thats exactly what i did. first i connected a 12 source to the vsv to see if it would click. it didn't. so i took a screw driver and a hammer and whacked the bracket that was holding the solenoid. When i reconnected the power it clicked just fine. The check engine light hasn't come on since

hope this helps someone in the future

oh and one more thing.
<-----what the hell does a guy have to do to get a third square around here? im not about to turn into a spam whore but god damn its been forever haha

Did you have to remove anything to get the canister out? I was able to disconnect everything but the wiring harnesses because I couldn't fit my hand in the small space to get to it. I am stuck with the p0446 code right now and I need to pass emissions by the end of this month.

IMG_1856[1]
I circled the trouble spot.

[enderswift]

I managed to change it it without removing anything. The solenoid was $95 from Toyota if I remember right

This post has been edited by enderswift: Jul 30, 2013 - 9:20 AM

[DIONYZUZ]

I managed to change it it without removing anything. The cab was 95 from Toyota if I remember right

I have a 99 GT and it looks like I'm going to have to remove the frame under it or something. Idk if anyone has gone through this problem too..

This post has been edited by DIONYZUZ: Jul 29, 2013 - 9:44 PM

[njccmd2002]

Do you have diagrams for this?

[njccmd2002]

i need to figure out if this would help to do my swap....

are the tanks in the celica pressurized?

this is what it is supposed to be for a rav 4



This post has been edited by njccmd2002: Nov 4, 2014 - 3:58 PM

[Smaay]

P0446 is the CCV, cannister closed Valve. that is actually in the engine bay. its the VSV that is round with 2 nipples on it at 90 degrees to each other. one goes to the intake between the throttle body and filter. and the other end goes to a hardline. the CCV is mounted just behind the fuel pump where the older charcoal canisters were mounted in the earlier years

[njccmd2002]

what im looking after is if our tanks can be modified for the newer charcoal systems.

Briefly looking at diagrams, Calif and Canada specs from 98 + were equipped with this system.

So i guess, our tanks should be pressurized, i need to see if i retrofit a 2007 rav evap system there.....