Need wiring location at computer

[JunkyardDog]

2003 Expedition. Getting P0446. I have power at the EVAP vent solenoid. I am not getting the computer drive signal. If someone could supply a pin and connector position, I am just going to run a new wire around it.

If I can get at least which connector, I can find the color coded wire. I just want to cut short unwrapping all of the connectors to find the one wire. I've tried looking everywhere in the forum and online for the info. I guess I am just shy of the right amount of patience right now.

Thanks in advance.

 

[Plati]

i got the whole manual from here once, don't know if it still works
https://www.scribd.com/doc/249677473/2003-Expedition-Navigator-Service-Manual

not sure what you want ...

this is from 2003 Expy workshop manual

 

[JunkyardDog]

Mr. Sticker, I thank you for the info. I signed up for SCRIBD. While I can find the document, it neither opens or downloads. It liked the paypal though. As to the additional graphic, I am already there. That is how I know that I am missing the signal from the computer.

I guess to be clear about what I was hoping to get...

One of the wires (Red) goes directly to the fuse box for power. I get that power and have already tested that it can supply the load. The solenoid clicks when ample power and ground is connected. Where before, it was not.

The other wire (Purple/White) supplies what I call an active LOW when it is to energize the device. This is equivalent to supplying the ground. It is not supplying enough ground. I am looking for the connector that the other end of this wire leads to. All of my average consumer manuals state that it leads to the computer.

There are multiple connectors on the computer. Without a little help, I will have to unwrap every connector until I find the correct wire. Since I already know this wire is compromised, even if I do find what I THINK is the correct wire, I could attach to another Purple/White that is used elsewhere. That is, of course, unless someone could tell me that, without a doubt, there is not another Purple/White being used.

I know I went a little long there. But, I am trying to be cautious and still do it right. I might even find, with my lousy luck, that the computer is at fault, and not the wire.

If someone were to have the knowledge (from a book or otherwise) where they could point me to part way connecting point to check, that might work too. I am just not sure how realistic it is that a part way connector is being used. One could always hope. Still, I might need to get to the computer again.

Anyway, does this fill in any blanks on what I was hoping to find?

 

[Plati]

It's a 68MB file I could gmail if you PM me with an email addy that can do 68MB. It's got a lot of diagnostic procedures. I tried looking for the computer side of that on the wiring diagram - didnt find it yet. I'm not even sure if the "computer" is the powertrain control module or something else. I think its the PCM. Spaghetti!

Geez that system is complicated (to me anyway, but thats not unusual).
is that solenoid normally activated (current sink on violet/wht wire) leaving vent open?






I'm just guessing which is dangerous, but it looks like that vent is normally open (solenoid not energized) and only energized (closed vent) to run the OBD test and then only for a brief period?

I'm way over my head here.

another idea?
https://www.expeditionforum.com/threads/vacuum-leak.43024/#post-385219

OR
https://www.expeditionforum.com/threads/p0446-evap-diagnosis.35317/

OR
bad gas cap?
https://www.ford-trucks.com/forums/1480057-p0446.html

 

[Hamfisted]

This is from my '03 wiring diagram book.
Should be the only violet and white wire on the PCM plug closest to the fender. Pin 36, but you'll have to verify visually. If you can make out the tiny numbers in this photo, pin 36 is the second one in from the right. You see there are 3 plugs on the PCM. The plug containing the canister valve (violet / white) wire is the plug ( looking in from the front bumper ) on the far left.

 

[JunkyardDog]

Hamfisted, You are a GOD-send! This is exactly what I was hoping to get.

MrSticker, I thank you for your reply as well. I may not need the download, yet. I've already stripped back past the first "knuckle" in the loom and found nothing. I wanted to test right at the connector and prove the computer is/is not the issue.

This does make me think if I am missing a step or 2, somehow. So this AM, I pulled out my hand vacuum pump. When the solenoid is activated, the vacuum pumps up. However, the vacuum does not hold for very long. More than a few seconds. I would think that it should stay until released. This may very well be my issue. So, the question is, "Should it hold tight?"

Another thought is, "how am I going to tell WHEN the computer is actually activating the solenoid?" I've been doing the Key on test. But, it may not be activating right at key on (which is why I went down the "search for the Purple/White wire road" anyway!).

I don't have the fancy scan tool to activate the solenoid. I know the solenoid works as I can activate it with power externally. What I think I need to do is insert a current monitor. When the solenoid is activated it will draw current. When it does, it will latch an LED on. It only needs to latch once to prove to me it worked.

 

[JunkyardDog]

The issue continues...
First. While the page provided above is GREAT information, the highlight pin is incorrect. I am posting the same page with corrected callouts.

For my issue, I have confirmed continuity from the fuse box, through the solenoid, and back to Pin 36 of the connector below. With the battery AND the computer connector disconnected, I was able to provide external power, to the fuse pin that connects to the solenoid and pin 36, and make the solenoid pull in. With my "fancy", homemade harness and meters, I was able to observe that absolutely no attempt by the computer to energize the solenoid was made. (BTW, I used the external power supply method to also prove my harness and test setup was valid.)

I ran this for several days and nearly 75 miles. All first thing in the AM after ~8 hours parked (and off). Viewed with Torque, all of my codes are clear except EVAP. I have the Ford test criteria and tried following it as best I can.

In my mind, that leaves 2 possibilities. Either the computer is defective, or I just have not provided enough time for the computer to trigger this test.

Personally, I say the "time" argument is BS. All tests (DTC's ???), with the exception of EVAP, passed the first day. Can anyone suggest anything on this?

 

[Hamfisted]

Good deal ! Junkyard do you know what the revision date is on your book ? Mine is May 2001, rev. 1 . Yours is easier to read the plug.

 

[JunkyardDog]

What I have looks to be only Section 100-01. The document properties does not show a release date.

 

[JunkyardDog]

A quick update...
The vent solenoid itself is, in my mind, is no longer suspect. The adapter I used to connect the hand vacuum pump was a bit, shall I say, hard. I've owned it a number of years. I acquired a new one and it held vacuum quite well. It may not have hurt that I also blew out the vent solenoid. I tested it multiple times and every time it held for well over 10 minutes. Once it held for over 20 minutes. The specification I am aware of is that it only needs to hold for 3 minutes. The new solenoid made no difference in the overall operation. I may be returning it, after all.

I built a harness to bring the connections up to the front seat. The point is that I can monitor progress, if there is any, while I can monitor the voltage and the current. I installed a bypass switch for the ammeter so if I don't have the ammeter connected, all is still considered "in-circuit". My ammeter has a hold function so that if it triggers, and I don't "see" it, it will still show.
Right now, all of the tests I see with the OBD scanner have passed, except the EVAP test. The light is not lit and it still states "Incomplete". Though I've put on a few miles (~75), it may need more still. I've been trying to follow the Drive cycle as outlined at the following site.

Ford Motor Company Driving Cycle

It was stormy today. So no testing.
I have also been looking at other signals,no matter how far fetched or if there is no code, to see if there is something that may be preventing the test. I found one. In Torque, I am seeing a FTPRES of ~4800. I'll be checking that as soon as I can. Can this be causing an issue with EVAP and not throw its own code?

Does anybody else have any ideas?