Corollas2019-23ToyotasTech

Search Corolland!

P0446 Code

by Sokudo, March 6, 2009



My 98 had this code trip the check engine light. I went to Auto Zone, and it refers to the EVAP/solenoid circuit. Anyone have any tips on this? The receipt gives me four possibilities, but I wonder if anyone else has had this.

I would reset the ECM and see if the code comes back. 90% of the time, it is an ECM glitch and will never come back. EVAP codes have plagued some of the 8th gen Corollas - can be tough to diagnosis effectively without the right equipment.

Most of the cases with the P0446 code, it is usually a bad VSV valve by the vapor canister or the VSV valve next to the airbox. Both can be checked out by apply power to them and see if they pass or block the movement of air (basically they are electric valves). Could also be a leak in the EVAP system - if you ever had a chance to look under the car infront of the gas tank - you'll see the vapor canister and a truckload of vacuum hoses. Any leak there could pop a P0446.

Also, do NOT get into the habit of topping off the gas tank, just pump until it clicks or stop short on a full fill up. Especially on our generation fo Corolla, it increases the chances of flooding the vapor canister - will cause all sorts of problems down the road. If the previous owner did this, could be why you are seeing problems now.

I would reset the ECM and see if the code comes back. 90% of the time, it is an ECM glitch and will never come back. EVAP codes have plagued some of the 8th gen Corollas - can be tough to diagnosis effectively without the right equipment.

Most of the cases with the P0446 code, it is usually a bad VSV valve by the vapor canister or the VSV valve next to the airbox. Both can be checked out by apply power to them and see if they pass or block the movement of air (basically they are electric valves). Could also be a leak in the EVAP system - if you ever had a chance to look under the car infront of the gas tank - you'll see the vapor canister and a truckload of vacuum hoses. Any leak there could pop a P0446.

Also, do NOT get into the habit of topping off the gas tank, just pump until it clicks or stop short on a full fill up. Especially on our generation fo Corolla, it increases the chances of flooding the vapor canister - will cause all sorts of problems down the road. If the previous owner did this, could be why you are seeing problems now.

Huh. I would like to not top off, but I think something is blocking the fuel line, because plenty of times I'll put the nozzle in, start, and it'll click off almost immediately. When I'm down 8 gallons. And it will continue to do it unless I pull the nozzle out a little, and fill up slowly. Very rarely can I go to a station and put the nozzle in, lock it, and let it fill up properly.

Is a vapor canister something that can be replaced easily/cheap/at all? Is it worth it to do so?

If the pump keep clicking off like that - sounds like a cut-off valve or fill vent hose is damaged/blocked. That could be causing the CEL code you are seeing. Vapor canister is not inexpensive - I would not attempt to replace that unless it is known to be faulty. Not hard to change, but takes quite a bit of time and patience - location is a little tough to get to (between the rear suspension and gas tank).

I wouldn't say it would be worthwhile to replace the canister, as I don't believe it to be the culprit in your CEL - any faulty component connected to the EVAP system could cause that CEL to pop up. Have to get the system checked out by someone with the right equipment (sniffer tester, diagnostic handtool, air compressor / vacuum pump, etc.)

If the pump keep clicking off like that - sounds like a cut-off valve or fill vent hose is damaged/blocked. That could be causing the CEL code you are seeing. Vapor canister is not inexpensive - I would not attempt to replace that unless it is known to be faulty. Not hard to change, but takes quite a bit of time and patience - location is a little tough to get to (between the rear suspension and gas tank).

I wouldn't say it would be worthwhile to replace the canister, as I don't believe it to be the culprit in your CEL - any faulty component connected to the EVAP system could cause that CEL to pop up. Have to get the system checked out by someone with the right equipment (sniffer tester, diagnostic handtool, air compressor / vacuum pump, etc.)

Sounds expensive (at least for me). If it's a valve, how hard is that to replace?

And I guess the biggest question is...is this something worrisome that I need to fix, or can I let it go for a while?

Unfortunantely, most EVAP related issues - the parts are relatively inexpensive, the labor to remove/install them is quite high.

On my car - I had several EVAP related codes right at 30K-34K miles - P0446 was one of them. The dealership indicated that nothing was under warranty because they assumed abuse (overfilled the tank). They wanted a little over $400 for replacing the vapor canister + noted that it could need more in parts. I told them to pound sand - and took it to another dealership. Paid $85 for diagnostic - I watched the tech work on my car, on and off for more than 3 hours - so I definitely got my money's worth. Ended up being a cut off valve - $35 part, $385 in labor - because they had to drain and drop the tank to get at it. I later bought the part at the dealership - drove my car normally until it was nearly empty (not completely, as the fuel pump is cooled by gasoline) - dropped the tank myself and replaced the valve. No special tools - took about 2 hours, start to finish - most of the time was spent cleaning the tank to prevent dirt from accidentally falling in.

You have to find out exactly what is wrong with the car's EVAP - once you find the defective part - then you can address the issue. Valves are pretty easy to change - simple devices that have an electrical connector for power (quick coupler) and atleast two vacuum hoses running to it. EVAP codes are relatively harmless - your case, it may be more bothersome, as it interferes with fillup. At worst, you might get a fuel odor from the read doors due to raw fuel being vented into the air - EVAP issues generally do not cause any driveability issues (its more emissions related). If you live in an area with e-checks or emissions testing, then this will be an automatic failure. If you have some time before you check or if you are not required to be checked out - you can let it go for a little while. But do not ignore it - the issues will only get worse, and eventually you might get into a very expensive repair (remember, the EVAP is connected to the throttle body to burn collected fuel vapors).

My daughter's 99 Camry needed one. If I remember correctly it was $250 for the part and $300 for labor...all paid for by the previous owner due to his unscrupulous behavior.

It's my understanding that if you need a solenoid they are available separately if you furnish the number off of the old solenoid.

Jay in MA

If the pump keep clicking off like that - sounds like a cut-off valve or fill vent hose is damaged/blocked. That could be causing the CEL code you are seeing. Vapor canister is not inexpensive - I would not attempt to replace that unless it is known to be faulty. Not hard to change, but takes quite a bit of time and patience - location is a little tough to get to (between the rear suspension and gas tank).

I wouldn't say it would be worthwhile to replace the canister, as I don't believe it to be the culprit in your CEL - any faulty component connected to the EVAP system could cause that CEL to pop up. Have to get the system checked out by someone with the right equipment (sniffer tester, diagnostic handtool, air compressor / vacuum pump, etc.)

Sounds expensive (at least for me). If it's a valve, how hard is that to replace?

And I guess the biggest question is...is this something worrisome that I need to fix, or can I let it go for a while?

Unfortunantely, most EVAP related issues - the parts are relatively inexpensive, the labor to remove/install them is quite high.

On my car - I had several EVAP related codes right at 30K-34K miles - P0446 was one of them. The dealership indicated that nothing was under warranty because they assumed abuse (overfilled the tank). They wanted a little over $400 for replacing the vapor canister + noted that it could need more in parts. I told them to pound sand - and took it to another dealership. Paid $85 for diagnostic - I watched the tech work on my car, on and off for more than 3 hours - so I definitely got my money's worth. Ended up being a cut off valve - $35 part, $385 in labor - because they had to drain and drop the tank to get at it. I later bought the part at the dealership - drove my car normally until it was nearly empty (not completely, as the fuel pump is cooled by gasoline) - dropped the tank myself and replaced the valve. No special tools - took about 2 hours, start to finish - most of the time was spent cleaning the tank to prevent dirt from accidentally falling in.

You have to find out exactly what is wrong with the car's EVAP - once you find the defective part - then you can address the issue. Valves are pretty easy to change - simple devices that have an electrical connector for power (quick coupler) and atleast two vacuum hoses running to it. EVAP codes are relatively harmless - your case, it may be more bothersome, as it interferes with fillup. At worst, you might get a fuel odor from the read doors due to raw fuel being vented into the air - EVAP issues generally do not cause any driveability issues (its more emissions related). If you live in an area with e-checks or emissions testing, then this will be an automatic failure. If you have some time before you check or if you are not required to be checked out - you can let it go for a little while. But do not ignore it - the issues will only get worse, and eventually you might get into a very expensive repair (remember, the EVAP is connected to the throttle body to burn collected fuel vapors).

 

Should I go to a Toyota dealer to find out the problem, or my own mechanic? I mean, is it more of an effective checkup to go to a dealer directly (even though I'm the third owner, so I wouldn't be going to the exact dealer), or just go to the mechanic I use normally?

If your mechanic is familar with imports like this Toyota, then that should be fine. Otherwise, take it to a Toyota dealership. You'll have to pay some diagnostic fee in either case, unless you are really on good terms with the independant mechanic. Once the real source of the problem is found, then you can take appropriate action to correct it.



Topic List