99 Camry 4-cyl Auto 124,000 miles. The 'Check Engine' light came on this week. I got an OBD II reader and it gave me the code P0446. That is something in the Evap. Emission Control. I have the Service Manual. The cchapter starts on DI-131 or something place like that. Obviously I'm having trouble reconciling what is on those pages with actually seeing what I'm supposed to see on the car. Where ought I to start looking for the trouble? My gas filler cap is ok. :-) And what does VSV stand for?
BTW, an addendum to the above: The OBD screen gave me "P0446, 1 of 1, mod $10, Evap Control System, Vent Ckt Malfunction". Is the reader telling me everything I ought to know? :-)
VSV is vacuum Switch Valve. You could start buying parts.
I had the same thing two months ago on my '97and made it go away by wiggling all the wires and connecting and disconnecting the plugs to the affected components. I adjusted all the hoses and inspected everything. Then I disconnected the battery to clear the code and the check engine light never came back.
I don't think the gas cap was the source of the Toytoa EVAP problems. I think the main reason for these lights is the newly design system back then is just not up to par. The carbon inside the canister can disintegrate and the powder will plug up things. Like a vacuum switching valve.
It's basically a vacuum switch that turns on/off a vacuum hose circuit. Sometimes the plunger and stick and it won't switch to the right circuit or properly turn on/off a circuit. Therefore setting off the code.
Here is a good explanatin by Erndog1369:
06-26-2004, 02:38 PM I have seen hundreds of P0446 codes on Camry like yours. 90% of the time it is caused by a bad tank by-pass valve (VSV) on the charcoal canister. You can check the valve by removing it and applying power to one pin and ground to the other. The valve should click... you'll hear it and feel it. Sometimes the valve sticks intermittently, and you may not experience it when testing it.
The P0446 can also be caused by a bad Canister Control Valve located on the air filter housing. You can test it the same way. This valve turns on and kind of clicks rapidly when power and ground are applied.
There can also be a leak in the evaporative system. This is very difficult to find, and you'd need special equiptment to test for a leak. Your best bet is the dealer. They see the P0446 everyday, and they'll be able to diagnose the problem relatively easily. Usually they charge 1 hour labor to diagnose it. From there you can repair it yourself if you want. The EGR valve will NOT cause the P0446 code. The EGR system have a few codes specific to it, like P0401. Your problem is in the Evap. Emission System.
Check the vsv on the Intake (air filter box) first. It's on the back of the air filter box and It's the easiest to get to. The removable one on the charcoal cannister is easiest to get to with the car on ramps. The bracket it is mounted to is held on with a tiny phillips head. Soak it in PBBlaster or Liquid Wrench and see if you can get it off to test. The vsvs run about $60 each. You can reset the codes and continue to drive. They don't affect performance, but they will get you in trouble in an emissions inspection.
Many thanks to the guidance I've received from all 3 replies. Gives me a good place to start. It shouldn't take me too long to run through the possibilities.
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