hey, I have a 2002 f150. I have been getting this code for months now, and I cannot make it go away... the wire coming off the purge solenoid at the canister has already been fixed before and it still appears to be in perfect shape, I cant find any other cracks of wear marks or anything in the wiring... I just changed the solenoid, and it still did not fix it. im not too sure what else it could be, any ideas?... I need an etest by Friday or my truck will be off the road and I really don't want that. any help would be great! thanks

 

The code is for the Vent function not the Purge if that helps.
Be awhere the fuel system testing can take quite some time to complete after repairs are made.
If your inspection allows the Evap system to be ignored for the purposes of passing inspection, I would clear all codes and let the system retest.
They will see it's Evap and might let it pass otherwise.
Good luck.

 

Can someone enlighten me as to the location of the canister and solenoid? Getting the P1451 all the time and when engine is under load for a minute vacuum is lost causing fan to blow at defrost only. It's a 1998 4.6L.

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Oh never mind it. A little deeper searching led me directly to the desired info. I love this forum.

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Looked over the wiring to the vent solenoid today and found no bad spots. Unplugged the solenoid and checked voltage at the plug, 0 with key off and 5.4/5.5 key on. Maybe the solenoid itself has gone south?

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You should have battery voltage back there, not less than 6 volts with the vent solenoid unplugged. You have a corroded or semi-open supply circuit (or a faulty measurement).

You can check the resistance of the solenoid coil. Probably several dozen to a hundred or two ohms. If it's open, it's bad.

 

Thanks. I thought I had read somewhere that it was to be about 4 volts. My bad. Thanks for clarifying that.

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Just a question here, would the P1451 code have any connection with the vacuum loss under load? Incorrect solenoid operation causing vacuum loss... I've been going over the truck and found a sizable leak so I'm thinking that repaired the switching to defrost but I haven't actually tried it. Any thoughts?

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No. P1451 is an electrical circuit fault.

 

Thanks. I just wasn't sure if the inoperable solenoid would cause a leak. Since it doesn't I will not make myself too concerned about that code for the present.

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Is there any known common chafe spots in the wiring for the solenoid?

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Frayed corroded, or damaged wiring near the canister has been the most common.

 

Thanks for the insight. Found it to be badly corroded at 2 spots between the canister and frame. Not a difficult fix at all! Engine light off, code P1451 gone. Thanks again!

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Great! Thanks for following up and letting us know what you found.

 

What could the code p1451 do to your car if ignored?