Need help troubleshooting code 0446 (already tried using new gas cap)

OK. I figured out that the voltage just goes across the VSV terminals. Everything seems to be working fine with the SVS for the EVAP.

I'm now trying to remove the VSV for the Vapor Pressure Sensor. Instead of the typical 8mm hex screw, there is a round philips screw attached the VSV to the body. And boy, that sucker's on TIGHT and very difficult to access. Any suggestions for removing this screw?

The design of charcoal canisters started in those years is defective. The problem is more likely in a check valve in the canister than your gas cap. The canister blows carbon out and plug your VSV and check valves. Check to see if your vacuum hoses at the EVAP VSV are clean for a simple test.

Check your EVAP VSV with theengine running, disconnect the hose to the VSV from the canister. You should hear loud vacuuming from the engine cycling rapidly as it pulls vacuum through the VSV.

The resistence can check out and you still have > O.B. wrote:

I just repaired (I believe successfully) a chronic case of OBDII codes

0440, 0441, and 0446 on a 2001 Camry CE auto tranny. The dealer last fall suggested a charcoal cannister replacement and "induction flush" for about $700 or so. I declined. Earlier this summer I ran tests out of the Haynes manual on the vaccum switching valves on the air cleaner housing and the charcoal cannister. The vsv on the air cleaner housing worked fine, but the one on the cannister did not throw when 12v was applied across the two terminals (the bracket is just a bracket, not a ground--hook one pin to ground and touch positive to the other, listen for a click). I replaced it for $47 and the check engine light has not come back on. The little phillips head screw holding to cannister vsv to the bracket is a bitch. I used an offset screwdriver to get it to move, lost it and then found it.

Perhaps carbon can get into the valve from the cannister. If so, maybe some pb-blaster will loosen it up.

I thought it laughable that the dealer would suggest that a can of cleaner dumped in the fuel tank (my guess for what an "induction purge" entails) would fix or prevent the problem in the future, especially when he started talking about how exhaust gas was involved in the problem .... That's just what I need--hot exhaust gas in the tubing leading to the gas tank....

Cheers, Mike Davis

"" wrote: > 1999 Camry LE, 4-cyl, made in Kentucky, Engine Light comes on, > Code 0446 > > From reading the newsgroups, the first culprit is usually the > gas cap. I > replaced it, reset the check engine light, and then it came > back on after 95 > miles of highway driving. > > I'm in need of some guidance for stepping through checking all > the sensors. > I just pulled the VSV for the EVAP. So far: > 1. The resistance between the two terminals is 32 ohms. > (normal) > 2. There is no air flow between the two inlets. > > The Haynes manual says to apply battery voltage to the VSV > terminal and then > try to blow air through the inlet closest to the terminal. > Which pin in the > VSV terminal (top or bottom) do I apply the voltage? I > suppose I need to > ground it as well? Is the metal bracket about the sensor > ground?

From Factory Service Manual 5S-FE, 1994

A) Inspect VSV for open circuit Using an ohmmeter, check that there is continuity between the terminals. Resistance (cold):

33-39 ohms If there is no continuity, replace the VSV.

B) Inspect VSV for ground Using an ohmmeter check that there is no continuity between each terminal and the body. If there is continuity, replace the VSV.

C) Inspect VSV operation a) Check that air flows from port E to port G. E = the vertical port just before the filter G = the horizontal port at opposite end of the filter b) Apply battery voltage across the the terminals. c) Check that air flows from port E to the filter. If operation is not as specified, replace the VSV.