2007 JK Wiring short - P0443 Code (system purge solenoid)

[Miguel1033]

Hi All,

I have a 2 door, 2007 JK, manual, The check engine light has been on for 2 years now. Im in Dallas, TX where they require emissions testing and if the check engine light is on you just wont be able to pass inspection, mind you I had the jeep on jack stands for the last 2 yrs upgrading the hell out of it myself so I focused on those mechanical upgrades leaving the code for last. Before I parked the jeep when the P0443 started I replaced the system purge solenoid valve, the charcoal evaporator canister, and a few other things, one at a time of course but nothing worked. I spent hrs researching and everybody and their mothers say the exact same thing "replace the purge solenoid valve", well, I've bought 3 purge solenoid valve so far.

In my JK, the 2 wires feeding the purge solenoid valve are blue/white and blue/brown, when you connect the voltmeter probes red(+) to blue/white and black(-) to blue/brown and you turn the switch key to the "on" position I read +12.03 VDC but interesting enough even tho I get 12VDC the purge solenoid valve will not react, meaning wont open, I bench tested all 3 (brand new out of the box) purge solenoid valve I've bought with a 12VDC power source and all 3 purge solenoid valve react meaning it "clicks" and I can test with a vacuum pump that it opens, but nothing happens when I connect it to the harness, again, even tho I get 12VDC at the connector.

What am going to do as my last resort is park it and take apart the wiring harness so I can inspect the integrity of the 2 wires going to the purge solenoid valve. But before I do this I wanted to check with the community and see if there is something else am missing. I hate to rip off all of the wire coverings looking for a break. I need some advice as to where to start and which other wires need to be checked besides the blue/white and blue/brown.

Thanks in advance,

Miguel
Dallas, TX

 

[BLACKJKU]

Are you sure you have a good ground at the wire harness plug? I always like to find out which terminal is the ground and put my test light clip there and then use the probe to test the power terminal. That way your testing everything at the plug.

 

[Miguel1033]

Here is an update, I decided to trace and tone test the 2 wires (dark blue/white and dark blue/brown) feeding the purge solenoid valve to find any break in them, tested them from the PCM connectors to the purge solenoid valve end, both tone up fine.​

Side note for future reference for anyone out there, (in my JK) the purge solenoid valve dark blue/white and dark blue/brown wires end at the white PCM connector, see photos bellow, dark blue/white pin 20, dark blue/brown pin 29.​

Something that caught my attention is that I didnt see any ground wire connected to the outside of the PCM case, is there supposed to be one? if not, does anyone have a wiring diagram or a place where I can get a FULL engine bay wiring diagram for this jeep so I can find where the common ground connections are for the PCM?​

BLACKJKU, I weld, I fabricate, I design stuff for my jeep but car electonics is not my forte, I can go as far a wiring accesories with switches, relay, etc, and not burn the jeep to the ground. I looked up how to find/test a ground fault (dynamic test) but am not sure I know how to do it to the purge solenoid valve while the car is running, any guidance is appreciated.​

​

Miguel​

 

[BLACKJKU]

I think you'll find the wiring here, https://drive.google.com/drive/fold...Uw?hl=en&resourcekey=0-ej7mkgiZxLzkp2ZxwpI28Q

If you can figure out which wire at the plug at the solenoid connector is the ground and the power you should be able to ground the test light clip on the ground terminal in the plug and then touch the hot wire and see the tester light up. That will let you know there is everything at the connector to make the solenoid work.

 

[Miguel1033]

I think you'll find the wiring here, https://drive.google.com/drive/fold...Uw?hl=en&resourcekey=0-ej7mkgiZxLzkp2ZxwpI28Q

If you can figure out which wire at the plug at the solenoid connector is the ground and the power you should be able to ground the test light clip on the ground terminal in the plug and then touch the hot wire and see the tester light up. That will let you know there is everything at the connector to make the solenoid work.

According to the document in the link you sent which validates my test and wire trace, page 18/45 the purge solenoid valve wires are Dark blue/white control and Dark blue/brown return, so it is a close control circuit, which led me to believe that either the PCM was faulty, the purge solenoid valve was faulty (unlikely due to the fact is brand new) or either connector, the connector at the purge solenoid valve or the connector at the PCM, upon close inspection I saw that the hole of the female pin 29 in the harness connector (see attached photo) to the PCM was slightly bigger that the rest, I closed it in ever so slightly with a pair of neddlenose pliers, connected everything back together and voila!!! freaking engine light is gone!!!

 

[BLACKJKU]

Ha, How about that, sometimes people just get lucky. A Dealer would have charged you about $1,000 for that fix.

 

[Danarch]

That is awesome, great you had the patience to follow it through. Not sure if I would have (or knowledge).

 

[mrjp]

Dam I hate electrical shit. So I’ll give y’all a just for digging in at.

 

[Miguel1033]

That is awesome, great you had the patience to follow it through. Not sure if I would have (or knowledge).

Dam I hate electrical shit. So I’ll give y’all a just for digging in at.

I H-A-T-E car electronics but hate dealerships even more, so I have to have patience...

 

[xstatic1971]

According to the document in the link you sent which validates my test and wire trace, page 18/45 the purge solenoid valve wires are Dark blue/white control and Dark blue/brown return, so it is a close control circuit, which led me to believe that either the PCM was faulty, the purge solenoid valve was faulty (unlikely due to the fact is brand new) or either connector, the connector at the purge solenoid valve or the connector at the PCM, upon close inspection I saw that the hole of the female pin 29 in the harness connector (see attached photo) to the PCM was slightly bigger that the rest, I closed it in ever so slightly with a pair of neddlenose pliers, connected everything back together and voila!!! freaking engine light is gone!!!

View attachment 119102

@Miguel1033. Would you believe I am having the exact same issue? I have a question for you, (hopefully you might remember the answer). My harness has a white cover on it and it looks like you removed yours to get to that pin. I am having a hard time removing it. Do you happen to remember how to remove it? I thought that sliding red clip was part of the solution, but looking at your image, I am not so sure anymore. Any ideas? Thanks!

Oh, I am in Dallas too BTW. Well, McKinney to be exaxt.