Need help troubleshooting code 0446 (already tried using new gascap)

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Old 27 Aug 2005, 11:37 am   #1 (permalink)
O.B.
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Default Need help troubleshooting code 0446 (already tried using new gascap)

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?
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Old 27 Aug 2005, 12:57 pm   #2 (permalink)
O.B.
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Default Re: Need help troubleshooting code 0446 (already tried using newgas cap)

O.B. 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?


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?
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Old 27 Aug 2005, 01:54 pm   #3 (permalink)
johngdole@hotmail.com
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Default Re: Need help troubleshooting code 0446 (already tried using new gas cap)

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 insufficient flow
through the VSV. The vapor VSV may be faulty, plugged up by carbon, but
very unlikely. So check the EVAP VSV again.

O.B. wrote:
> O.B. 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?

>
> 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?


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Old 29 Aug 2005, 03:04 pm   #4 (permalink)
ycleptor2@cs.com
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Default Re: Need help troubleshooting code 0446 (already tried using new gas cap)

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

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