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Toyotapro, ASE master tech
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Experience:  ASE Certified, 10+ years Lexus and Toyota Certified
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99 Toyota Corolla with the check engine light on and the code

Resolved Question:

99' Toyota Corolla with the check engine light on and the code indincates the evap system/charcoal vapor cannister. Have tried 1 - changed entire charcoal vapor cannister from at wreck (due to cost) with 60,ooo km and 2) changed the fuel cap - again from a wreck due to cost... and neither of these efforts have worked the same code occurs. The only other notable thing to do with this problem is that there seems to be a lack of pressure from the fuel tank when removing the gas cap no matter how full to empty I get the tank.
Submitted: 8 years ago.
Category: Toyota
Expert:  Toyotapro replied 8 years ago.
What code#?
Customer: replied 8 years ago.

Hi Peter,


Thanks for your prompt response - it was a nice surprise.


Had to the codes written down and had to find them for you...


hard codes: P0441, P0446


soft codes: P0440, P0441, P0446


I really don't know the difference of "hard" and "soft" codes - but those are as provided to me from AutoZone...


Thanks for your assistance.

Expert:  Toyotapro replied 8 years ago.
Thank you for the reply. There is a known issue with the P0446 code that can trigger other codes. This is due to a defective engine control module. I need the part # XXXXX your computer to determine if this is the issue or I can provide the file/bulletin for you. Thanks
Customer: replied 8 years ago.

Where is the ECM located - the center dash console - may be behind the ash tray??? That should be fun to get at if so......


But - IF I looked at the correct bulletin - based on the VIN , i don't think that the ECM would be covered under that bulletin (but, I most certainly could be wrong...)


Also - this initial problem started about a year ago... and at that time Toyota obtained only 1 code for the evap and wanted a bucket of cash for change the charcole vapor chanister - and also said to drive as as it may go out due to a long period of very humid weather and that a rash of these were occurring...

Expert:  Toyotapro replied 8 years ago.
THank you for the reply. The ECM is behind the glove box. Get me the 10 digit part # XXXXX the ECM and I will determine that for you.
Customer: replied 8 years ago.

Thanks again - as I don't got the manual - how hard is it to get to the ECM behind the glove box? If it's not so great of a task - i'll be happy to get you the # XXXXX it...

Expert:  Toyotapro replied 8 years ago.

You may be able to lay on your back and read it, if not then remove the box. When you open the dor I believe there are 3 phillips head screws at the top, then there are 2 10mm bolts on the bottom of the box (1 on each corner). This only takes 2 minutes to do. Keep me posted.

Just curious...if you don't have any manuals how have you been diagnosing and repairing the car?

Customer: replied 8 years ago.

online info - and chatting with other mechanics along the way - but the car has 256,000km on it - and other than this - the car has be problem free :) and I have had no real need for a repair manual... as I am very well equiped to deal with to much (although I wish I were...). Also - I do have a good friend from work that can do most work and maintenace on my cars... works cheap.... but he will pick and chose the jobs...


the last mechanic I spoke with (with out the specific codes - just general evap and vap canister) wanted to smoke the system to see if any leaks.


thanks for the help - if I can't get to it tonight - dark/cold - I see if tomrrow is better.

Expert:  Toyotapro replied 8 years ago.

Thank you for the reply. Just get me the part # XXXXX you can and we will go from there. Yes a smoke chek is a GREAT way to test this system if you have access to that equipment. We still need to eliminate the ECM update as well. I will talk to you tomorrow. Have a good evening!


Customer: replied 8 years ago.
Got the glove box out and there is nothing there - just plack plastic... however - if I remover the ash tray - I think I see something that might look like the ECM..
Expert:  Toyotapro replied 8 years ago.

ECM is a grey metal box BEHIND the glove box with 3 connectors, if you look under the hood you will see where the engine wiring harness enters the cabin to the glove box area, this is where the ECm plugs in:


Customer: replied 8 years ago.
Thanks for the pic - I'll try and see tomrrow with better light may be better luck :)
Expert:  Toyotapro replied 8 years ago.
Customer: replied 8 years ago.

um - behind the glove box is the cooling unit and the blower unit


Expert:  Toyotapro replied 8 years ago.
My apologies, ECM is behind the center lower finish panel in the image I posted before, this year corolla is a little different
Customer: replied 8 years ago.

no prob and thanks again - hope to get back to you soon -



Customer: replied 8 years ago.

got it as follows:



the # XXXXX the bar code : *1753003370T*






TN175300-3370 12V









That was fun (lol).....

Hope that helps you/us.

Where can I find a copy of the bulletin for this?

Thank you.

Expert:  Toyotapro replied 8 years ago.

Ok your car has the updated ECm in it already so we can eliminate that, no need for the bulletin.


Here is an outline of your issue, click below:

Customer: replied 8 years ago.
That might be good news... Thanks for checking that out for me.
Expert:  Toyotapro replied 8 years ago.
click the link I posted above
Customer: replied 8 years ago.
link broken?
Expert:  Toyotapro replied 8 years ago.

Sorry, let's try that again:


Expert:  Toyotapro replied 8 years ago.
Sorry I post all my LARGE files to this site and it appears to be having technical issues right now, can you check back in a little while? I just submitted a report to get this resolved.
Customer: replied 8 years ago.

Sure - thanks. Care to e-mail it to me?

Expert:  Toyotapro replied 8 years ago.
Sorry for the technical difficulties, I have tried loading a few different ways, I have e-mailed this file to just answer administration and requested they e-mail it directly to the e-mail address you have on file. Thank you.
Customer: replied 8 years ago.

Thanks - I see that covers DTC P0441 and 446, but nothing for the 440. It seems like 440 is fairly generic - is that correct - and therefore no real troublshooting for this?


Also, will any generic/cheap code reader/scanner accomplish what I need to try and do? Canadain Tire has some for 40 or 50 dollars - but do I need one that accomplishes a specific task - like activation on some of these components for testing? Thanks.

Expert:  Toyotapro replied 8 years ago.
Yes you need a scan tool that can activate the evap components and also monitor the vapor pressure tester, a basic scan tool will not do this unfornutely. es p0440 is a general code for a leak. The 441/446 are specific to that area outlined in the file I forwarded to you, you will see a "map" on page 1......anything within the dotted line is a possible area of concern, if you have no leaks in lines it needs to be tested, a evap smoke machine is helpful here also, my feelin here is you will most likely have a bad or wrong canister.
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Customer: replied 8 years ago.

Thanks for now - I might just get the technical dignostics from my mechanic uesing the smoke test and get his opinion/estimate... and take it from there as I don't think that I can get my hands on the scan/multimeter/pressure pump (although cdn tire has a cheap one...) I just watched a smoke test video (


Although there is supposed to be a garage around here somewhere that rents you the service bay space to work and I think they have a tool loan system included for DIY while there... so I'll have to look into that. May be they have a smoke test for loan as well as the rest of the equip.


Thanks for the much needed assistance and providing an understanding of the nature/solution to this problem - and I hope that we may be able to communicate on this issue further in the future. Unfortunately at this time I am on an indefinate lay off... so any extra expence for tools and parts at this time may not be feasable; thus, have to waite for now. Just figured that I'd learn what I could since I have the time to play with the car (and I enjoy the challenge - although I'v been known to make things worse - lol).