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2005 Rubicon, 4.0, Manual trans, 2.5” lift, 33” Duratracs.
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Discussion Starter · #1 ·
2005 TJ Wrangler, 4.0, manual.
I‘ve been battling the gremlin check engine light in this Jeep for some time now. Removed the front cat converters when I first purchased a few years ago to find the last owner had hollowed out the converters. Replaced the unit and installed 4 factory O2 sensors. To this day I’m still getting check engine lights for all the sensors.
Today my wife called and said the Jeep was running ruff and had stalled in the parking lot at work.
I ran a diagnostic with my scanner and showed, P0300 multi cylinder misfire, P0340 no camshaft signal @ pcm, P0335 camshaft position circuit, and one for each Oxygen sensor heat circuit too high. I disconnected the battery cables and held them together for about a minutes. Started up the Jeep and it is running great again.
I know there were issues with this years Jeep computers from reading the forums. I read some where that somebody was rebuilding these units and people were having good luck with them, but I cannot find the source. If anyone could help me with a good source that would be much appreciated.

thanks, Greg
 

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Welcome to the Forum.
WranglerFix is who you are referring to. The owner (Mark?) should set you at ease. I have yet to hear of issues with his 05 and 06 PCM’s or as some call them ECM’s. You 05 and 06 people are fortunate.

Let us know your progress.
 

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The WranglerFix.com PCM resolved this problem for me.
 

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18 months ago I threw a code for each of the 4 sensors. Looking at the schematic the only common wire is the ground. I found the ground...pulled the stud...cleaned the block and all terminations.

Didnt aolve the pronlem...took it to the dealer and told them I need a new computer. They were insistent that all 4 sensors failed at the same time. So they replaced all 4.

Codes popped again 70 miles later.

Dealer made good on it and credited the sensors. New computer installed and issue didnt return.

2005 ...same as yours. Sounds like yours is going even further south...

Do make sure your connectors are firmly in the computer...I had one half out once and got lots.of codes. Ensure your harness isnt rubbing thru amywhere. Then I wud agree ur up for a computer..
 

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2005 Rubicon, 4.0, Manual trans, 2.5” lift, 33” Duratracs.
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Discussion Starter · #5 ·
Thanks for all the reply’s. Talked to Mark at wrangler fix and ordered up my replacement computer today. He gave me a 15% off discount code and he is getting it shipped ASAP!
Thanks again, Greg.
 

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Transmission control is one big issue addressed. My friend’s 05 locked up and became a paper weight. He actually went through two replacement transmissions trying to sort it out. He was pretty downcast one day when I stopped by to visit and told him about WranglerFix. A new PCM later he had a perfectly shifting Jeep. Since then I’ve heard of other issues remedied by their PCM’s, but I guess that figures. PCM’s fail in multiple ways. If I remember correctly, it’s the transmission gremlins in the 05 and 06 PCM’s that motivated Mark to find a solution at ground zero.

Just visually, my PCM has three plugs and my friend’s has four. His extra one is transmission control. Apologies to Mark if I got anything wrong.
 
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Seems so. I think Mark recently became a member of ROF. Maybe he’ll reply here. His forum ID is WranglerFix.
 

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IIRC, Chrysler went to a different language in '05 across all brands. In my opinion, they tried to short cut the wrangler since they knew the JK would be out in '07, so they didn't want to spend any development money on an out-going model.
 

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Makes me wonder if I should just pre-emptively replace and/or sell my happily working stock PCM
 
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If it were me, I think I would flat out buy one and test it and keep it on hand. I do know that WranglerFix does need cores though. Returning a core may be a requirement.
 

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At least in my case WranglerFix did not request the old PCM. The new unit is physically different, but plug compatible. I say new. It is a repurposed unit removed from another application.
 
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Interesting. So its mostly for automatics?

i wonder what changed in 05 that does not exist in the 03 or 04 computer programming
The TCM (tranny control module) is integrated into the PCM for the '05/06 automatic tranny models. I suppose the manual transmission has no need for a module. other than that, I don't know what the differences are.
 

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Earlier TJ's used a JTEC controller (Jeep Truck Engine Controller) the 05/06 used a NGC (Next Generation Controller) with integrated transmission control. The NGC was probably developed for emission control more than anything and was a temporary fix to get to the JK platform which uses a controller similar to a lot of product we still have.

I used to remember more information but I suspect that the two controllers could have been made by different suppliers. Emission controls were still difficult and the manufactures were having a hard time with older design engines like the 4.0.

Back then like it is now engine and electronic development is driven by the governments clean air mandate.
 

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The WtanglerFix PCM has been a flawless fix for my PCM gremlins in my 05 Rubi. In fact, it improved drivability and fuel mileage noticeably. Maybe mine had degraded over time and I didn’t notice, but it really made a big difference. I’m about 12 months into the replacement.
 

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Welp
Put one more check mark into the Plus Column for buying a Manual 2004 Rubicon.

Maybe we need to get new ECU's for cows so they won't fart as much.
:ROFLMAO:
I have one, but I'm not sharing... And I will NEVER sell it!

No matter how "automatic" they try to make things the automatic transmission does not know there's a incline ahead and that it's best to keep up the momentum in a lower gear. Think about it, if you have to continually override the automatic transmission your machine is actually working against you. I suppose that if you get used to this then you have programmed your brain to automatically override your automatic machine. I have "control issues."
 
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