p0446 odb2 code

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Apr 24, 2012 | 07:25 AM

pjrick

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p0446 odb2 code

I have a 2005 ford f-150 5.4 l that the cel light came on. when it first started it did not give me a code but said I had a small emmisions leak. In a day or two it finally gave me a code (p0446). I pulled out the evap control purge solenoid to ensure that it was not plugged. I checked the voltage @ the plug/ with the key on it is giving 14 volts. when i plugged the valve in it would not shift. I took the valve out and jumpered it directly to the battery and it seems to work fine but when I plug it into the harness it does not work, I Cleaned all connections I could going back to the pcm and doublechecked voltage @ the plug and still have 14 volts but will not fire the solenoid. the coil omhs out @ 63omhs. I am going to try a new valve if anyone has any other Ideas pleas pass them on.

thanks
Paul

Apr 24, 2012 | 11:45 AM

pdqford

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From: Central NYS

Quote:

Originally Posted by pjrick

I checked the voltage @ the plug/ with the key on it is giving 14 volts. when i plugged the valve in it would not shift.

Its only going to "shift" when the PCM figures all parameters are correct to do an EVAP Monitor test.

The P0446 code is saying that the PCM read a voltage outside the allowable parameters while the PCM was driving it at a specific duty cycle.
(At 0% duty cycle it should read approximately battery voltage and at 100% duty cycle it should have a minimum voltage drop of 4 volts.)

Your reading of 63 ohms is within spec so I would check the ground side of the circuit very closely.

After cleaning all the connections and clearing the codes have you tried it to see if the light comes back on?

And just to be sure we are looking at the same part, this is the canister vent solenoid located under the rear of the vehicle?

Apr 24, 2012 | 03:05 PM

pjrick

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p0446

Jim,
You are correct this is the canister vent purge solenoid located under the rear of the vehicle just above the spare tire. Question is there anything else in the electrical circuit for this solenoid that may be be interferring with it ? Would it be preactical just to run a new pair of wires of the pcm back to the solenoid ?

thanks
will keep you posted

Apr 24, 2012 | 03:56 PM

Papa Tiger

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From: Near Cal. Avenue

If you clear the puter it will run an EVAP test within 15 miles if the fuel tank is 1/4 to 3/4 full of gas and the weather is warm enough for gas to evaporate. Otherwise it will wait for a warm day. It won't run the test in coldr N hell weather. Will just state Evap test ? on the I/M data. Make sure your Vacuum hoses and clamps are tight. No cracks or deterioration to the hoses.

Apr 24, 2012 | 05:08 PM

pdqford

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From: Central NYS

Quote:

Originally Posted by pjrick

Would it be preactical just to run a new pair of wires of the pcm back to the solenoid ?

Well, only one wire runs to the PCM. Since you already proved you have B+ voltage on one wire, it is getting voltage through its fused feed. The other wire (Violet with white stripe?) goes to pin 61 (IIRC, that is in the passenger side(?) connector on the PCM) and is pulled to ground by the PCM when it decides to run the EVAP test.

You could unplug that connector from the PCM and ohm out that wire from the CVV solenoid connector back to pin 61 of the PCM connector. (Your looking for about 4 ohms or less resistance.) Also, check pin 61 to be sure it isn't growing "green stuff" (trademark