How I fixed the Evap Leak in my Toyota Celica.

Disclaimer, this is what I DID for MY CAR. If you are having issues with your car, I would recommend a professional diagnosis. I am a DIY guy, a DIY guy with mismatched vacuum lines.

I switched the vacuum lines on one of the evap valves, then my P0446 code went away. 300+ miles on the car and the codes haven't come back. I had a CEL come on, and I didn't bother scanning it. It turned off 2 days later.

As far as I'm aware, my evap leak is gone, but my voltage regulation issues with 'potentially' the alternator still exist, but this car is getting a rebuilt engine, so I don't give a darn.

If you are getting any codes, make sure

1. Your Gas Cap is OEM, I know the darn cap is like $30 from the dealership, but it works. If you want it cheaper, you can try to find an OEM one from a junkyard, just make sure you clean the plastic threads with an alcohol wipe, and make sure the o-ring is clean and can seal gases.

2. Your Fuel Filler neck isn't rusted beyond repair.

3. The O-Ring in your gas cap is clean and lubricated. As a "temporary" fix, wipe down the cap and filler neck mating points with a paper towel and WD-40.

4. All vacuum lines aren't cracked or have obvious damage. They were cheap to replace with silicone ones, but you still have to remove the muffler to get to the canister.

5. Each car has its' history, but there are low chances that wires are damaged unless the vehicle has water leaks or known damage to the internals.

6. The valves don't break too easily, especially after 25+ years, but it doesn't hurt to inspect them electronically and physically.

7. The canister is hefty at $250+ new from Toyota. A new aftermarket one might be alright, but it is mainly the electronic valve mounted on the canister that NEEDS to be OEM. I had a Dorman valve on my canister, it made my issue worse.

8. Make sure all vacuum lines are going to the correct spots.


I wasn't planning on making a video like this until I was 100% sure my evap leak was gone. My MPG is still really bad in my car due to degrading parts, but I am confident about my P0446 being gone since it hasn't shown up in 300+ miles after switching the vacuum lines around.

This video is for the guy who asked me about my evap leak. I am no expert, but I will try to answer some questions in the comments.

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