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Hey, everyone! I'm finally caving in and asking for help. I've done hours upon hours of research on this issue and can't seem to find what I'm looking for. I had this code come on and immediately just thought I'd replace the solenoid. When I went to put the new solenoid on, I realized the wires were cut about 6" from the vent solenoid. So, I put the new one on and fixed the wires with heat shrink butt connectors. I immediately threw the same code again.
At that point a light bulb kind of went off in my head and I realized that I definitely have a wiring issue as the code throws almost immediately. So I started to trace the wire from the harness at the vent solenoid. I noticed as it went through the body plug to the inside of the trunk the wires were broke there as well. So, I fixed those as well, yet again with no luck. I then decided I was just going to cut the wires inside the trunk so I could eventually just wire them straight to the new plug that I had to get for the new vent solenoid. I figured that would reduce the number of connections and limit future issues.
I then used my multi-meter to test the wires for power and discovered that the white wire was reading around 380 MV and the orange wire was receiving no reading at all. In full disclosure, I'm not a mechanic, or any type of super experienced guy with electrical diagnostics. I do however love to learn how to do things as my 5 year old boy is always with me and I want him to learn right along with me. I'm just at a point where I don't know what I should do next. I can't find where there's a fuse for this anywhere, or any type of wiring diagram for that matter.
My thought was, if I could find where the wire originates from, I could start trying to trace it towards the back and see if I can find a fault in it somewhere. I haven't traced the wire from the back any further than the front of the trunk where it disappears again. As far as diagnostic equipment is concerned, I've just got a one way OBD-II reader and a multi-meter. A good friend of mine has a Snap-On diagnostic tool, but he is gone on vacation. So, I"m just looking for some ideas on where to turn to next.
This code doesn't affect the ability to drive the vehicle in any way, it's more of just a challenge to myself at this point. I really appreciate any advice that anyone may have, and I hope I've explained things well enough so you understand where I'm standing at the moment. Thanks in advance!
Www.eautorepair.net
will have wiring diagrams that you need. With your car one of the wires should go to the pcm which should be located in your engine air filter box next to fender in front of engine bay. You will have 2 big connectors on the pcm C1 and C2. The gray looking cover that protects the wires will have 6-8 tangs on them. Use a small screwdriver and pry them inward on the connector and pull up it will come free. Just be gentle as you dont want to break too many off. Then use a t pin from a craft store like hobbie lobby or walmarts sewing area and push that into connector terminal (backprobing) from backside with connector connected and against the wire for the vent solinoid to check power for circuit. The ground wire should connect to a ground point near vent solinoid so in the trunk somewhere.
So if I buy the wiring diagram, then I find the correct wire in the PCM for the vent solenoid and that is the wire I back probe? I then use my multi-meter to check the T pin for power at the pcm? When you talk about the ground, are you meaning to ground one of the 2 wires that go to the vent solenoid to ground near the trunk?
thisdj1 wrote: I then used my multi-meter to test the wires for power and discovered that the white wire was reading around 380 MV and the orange wire was receiving no reading at all.
Excellent! The WHITE wire is the control wire. The 180mV, that you are seeing on it, is likely a bias voltage. Seeing this indicates that the control wire is good. It is this bias that the computer uses to detect problems. When the circuit is complete/intact. The 180mv will be raised to battery voltage, do to the constant power that is SUPPOSED to come in on the ORANGE wire, and through the solenoid winding. The computer KNOWS there is a problem because it does not see the voltage as battery voltage. Check the Canister Fuse (behind Right side of dash).
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
thisdj1 wrote: You've given me some hope here! However, looking at the fuse block diagram, I don't see a canister fuse for a 2005 Grand Prix.
Make sure you are looking in the correct Fuse Block. There is more than one. Are you looking under/behind the right end of the dash, in the passenger compartment?
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
There's 12 fuses in that panel, labeled A through L. But nothing that says anything about a canister or anything related to EVAP. I checked the diagram for the one under the hood as well and it too doesn't say anything about a similar fuse.
Yes to first two questions. The solinoid will(should probably say might) have one of the wires grounded. The one wire you read 380mv on could have been your ground. But you should confirm that with wiring diagram first to make sure. If it was the ground that voltage reading is high you should see no more 100 mv on a ground. But we will go over this after you check the power at pcm and verify which is your power and which is your ground. As for your negative lead from dmm touching a bolt or bare metal will work for ground point otherwise if lead is long enough best connection is battery negative.
Well, I guess, start by checking all the 10 amp fuses. I'll see if I can come up with more helpful guidance.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
I may owe you an apology. I'm not back to the vehicle yet so I haven't confirmed it with my own eyes! I did an online search and didn't see a fuse for it. However, Matt T posted a link to my owners manual and it does appear that there is a canister fuse. I'm on my way there and I will confirm it one way or the other. Again, sorry for any misinformation.
Hardtopdr2 wrote: As for your negative lead from dmm touching a bolt or bare metal will work for ground point otherwise if lead is long enough best connection is battery negative.
Trusting a bolt, or frame, as a GOOD ground is risky. Keep in mind that it might NOT be a GOOD ground, especially if your readings come up different than you expected. Negative battery post is ALWAYS the best reference point. A pair of jumper cables can help make it accessible. You only need to hook up the NEGATIVE cable. Now, you have a mobile NEGATIVE battery post (or, the next best thing).
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
Hardtopdr2 wrote: As for your negative lead from dmm touching a bolt or bare metal will work for ground point otherwise if lead is long enough best connection is battery negative.
Trusting a bolt, or frame, as a GOOD ground is risky. Keep in mind that it might NOT be a GOOD ground, especially if your readings come up different than you expected. Negative battery post is ALWAYS the best reference point. A pair of jumper cables can help make it accessible. You only need to hook up the NEGATIVE cable. Now, you have a mobile NEGATIVE battery post (or, the next best thing).
That is a genius idea! Even for future use. It seems so obvious now, I can't believe I've never realized it before now!
Alright, I owe an apology to the forum. I found the fuse, it was blown, I replaced it and had 12v at the orange wire at the solenoid. I tried to exhaust all resources before coming here and wasting anyone's time, only to do just that. I really appreciate the help from everyone though. Now, I'm going to make another post for the last code that keeps messing with me. Thanks again everyone!
thisdj1 wrote: Alright, I owe an apology to the forum... I tried to exhaust all resources before coming here and wasting anyone's time, only to do just that.
No apologies necessary. The purpose of this forum is to help each other learn. That's why it exists. We are ALL, still, learning. There is ALWAYS more to learn.
Glad you got it fixed!
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
The purpose of this forum is to help each other learn. 
That's why it exists. We are ALL, still, learning. There is ALWAYS more to learn. 