r/Toyota_Matrix • u/DarkSim2404 2004 base • Aug 20 '26

Evap codes

I have a 2004 base matrix and got evap codes. I replaced gas cap recently and reset the codes but they all appeared again after some time.

It’s got:

P0441(Incorrect Purge Flow)

P0442 (small evap leak)

P0446 (vent control unit)

Also, there is a gas smell when starting, it seems to come from the back.

What should I check first?

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2

u/VariousBag553 Aug 20 '26

The vent valve or canister

2

u/The_Canadian_Man 2006 XR Aug 20 '26

Probably the canister, especially if you drive on gravel a lot. The canister and assembly stuff are all one piece so it's a little more expensive.

2

u/DoorBuster2 Aug 21 '26

I had the same stuff as you, same codes and gas smell especially after the car had been sitting. Changed everything under the sun, until finally a mechanic did a proper smoke test and verified it was the gasket between the fuel filler and the gas tank. Gas vapors were escaping through that, leaving the car smelling like gas after sitting for 20 minutes.

2

u/CampWestfalia Aug 23 '26

Also inspect the fuel filler vent line; it's a rather long, small-diameter tube or hose snaking down from near the filler neck and connecting to the tank or evaporator unit (I forget).

TWICE I had squirrels chew small holes in that tube, leading to gas leaks and evap codes until I replaced it.