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I wasn't going to start a new thread on this subject since it is well documented on every forum Jeepers use over the last 10 years, but since I have replied to old posts here, and have sent PM's, ALL with no replies, I think this warrants yet another post on the subject.

I will see this thread through to a RESOLUTION, SOMETHING EVERY OTHER EFFING THREAD WORLDWIDE FAILS TO DO.!! If I have to replace the PCM a dozen times, I will write about the who and where. If I get a good PCM, I will tell you the name of the company!!! a novel idea!!

The basic background:
a new to me 2006 Wrangler LJ
with 13,000 miles.

Everyone knows about the hard shifts so I won't waste my time typing the details out.

I took it to the dealership today for some proper computer based diagnostics. This didn't tell me much...

The P56044702ad download on the factory PCM, was updated to the newest version available, P56044702AE. The tech was able to install the update no issues, but when he tried to do a quicklearn on the PCM to clear all of its learned behaviors, is where things got interesting. He wasn't able to do the quick learn because the transmission range sensor was so far off that his computer attached to the jeeps OBD2 port, was locked out.

It was hot today in Houston area for early June. 90's ish in the shade, water temp was 190, transmission fluid ZERO DEGREES, then -3 degrees. This is what causes the horrific shifts. a minute or so later the fluid temp was 300 degrees. both of these extremes in temperature were beyond Jeeps diagnostic computers ability to do a quick learn.

When the temp sensor reads very low the PCM holds the transmission in gear longer, resulting in the horrific shifts.

The high temps makes the tranny shift weird too, it just doesn't hammer you so it may go un-noticed.

Even though I had a stack of paper I brought with me today, documenting the issue ad-nauseam, the mechanic thought the problem is a bad Range / temp sensor.

The Mechanic said the dealership (ClearLake Dodge) has a "Transmission in a box" (it was on loan to Gulfgate dodge today!) This thing plugs into the transmission somehow and they can simulate speed, gear position and temperature, among other things. He said that if they hook it up and tell the transmission that it is 200 degrees, but it reads -3 or +300 on the scanner plugged into the OBD2, it would be a bad PCM ( maybe) if it reads what the box tells says the temp is, its the TRS.

the general consensus has one basic conclusion. BAD PCM. Then I read the below post. He had the exact symptoms the the rest of us are having, but it was repaired with wiring.. It's one of the last posts in this thread: http://www.wranglerforum.com/f210/2006-jeep-wrangler-auto-transmission-98702.html


@DamnGroundCable may have solved the issue by replacing the Damn Ground Cable.... I was hoping would come back to shed some light on the subject.... apparently replacing the Damn ground cable for the transmission temp sensor cured his issues as he was never heard from again...
Originally Posted by DamnGroundCable View Post
Vehicle:
Jeep Wrangler 2006 Unlimited. 46,000 miles.

Problem:
Jerking/Hard shift from 1st to 2nd gear. After a few hard shifts, the issue would go away. I also could let the vehicle idle for about 10-15 minutes and it would shift normally.

Troubleshooting done by the Chrysler dealership:
-Error codes from PCM stated that there was an issue with the transmission temperature. Me too
-Disconnecting the battery made the jerking issue temporarily go away. me too
-The issue started in September of 2014 and wasn't resolved until October of 2015. Luckily it was under warranty.

Chrysler performed the following services in order:
-Rebuilt transmission - drove fine for about 5-6 months. 1
-Replaced valve body - because issue returned
-Flashed the PCM
-Replaced PCM and flashed with updated software NEW PCM didn't fix the issue, more on this later...
-Different dealership flashed PCM again and checked connection cable to transmission
-Did some maintenance in regards to cylinders (I don't remember completely, but it had to do with cylinders and transmission)
-Rebuilt transmission again 2
-Replaced Transmission completely 3!!!
-Finally replaced a ground cable associated with the PCM, and the Jeep has been working fine for almost two months

On the last visit when they replaced the ground cable, the dealership was saying that vehicle was showing a -3 degrees difference in the temperature. not a -3 degree difference, just -3 degrees I will link the photo

Anyways, guess the PCM was being shorted out.

The link to the picture of his maintenance receipt was DamnGroundCable's third and last post on WranglerForum...



So, I am searching for the answer to this common and pain in the ass issue, when I get a resolution, I will post it here, AND make myself available for discussion
 

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Discussion Starter #3
You Happen to Drink a lot of Coffee yesterday evening?
haha.. I typed that over several hours. Type some, kid stuff, type, dinner,....


I wanted to go back and make some edits, but editing posts isn't allowed for some bizarre reason.
 

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Discussion Starter #4
DamnGroundCable had the PCM replaced at the dealer and it didn't fix the issue. This left me scratching my head. even though he had the exact symptoms as everyone else his problem looks to be a wiring issue...

Bad PCM's:

This shift issue was/is so wide spread, that it lead to a shortage of PCM's for replacement. That problem appears to have been corrected as far as the availability goes with one HUGE BUT.....!

A quick google search will lead to many computer replacement outlets. Great!

Umm, NO. many of these places have horrific customer reviews. The PCM's that are failing generally don't show any major fault codes and are turned in for cores.

These core are tested and cleaned,and since they aren't throwing codes are put into boxes and sold to some other person with a bad PCM...

In my search for a resolution I have read many threads on many forums, some people have been through 3 or more PCM's before they get one that cures the bad shift.

I have spoken to 6 companies that offer PCM's, none of them replace all of the chips on the board. So while some claim to have re manufactured PCM's, none that I found are truly reman, they are rebuilt IF bad parts are found....

The biggest frustration I have with all of this is that forums are thick with problems but lack solutions. People have replaced PCM's and have had their shift issues cured.

It would be nice if they'd stick around long enough afterwards to post WHERE they got the PCM....
 

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Discussion Starter #7
I took my jeep back to Clearlake dodge Jeep today and they said they did the transmission in a box test. The service advisor said that the test concluded that it was NOT the PCM, but it was TRS... Because of the fact that the transmission shift issues are very well documented, I tend to disagree with this finding, and cannot actually verify that the test was even done....

The service writer suggested, and I agreed to a $580 service. A new TRS, filter fluid and labor. When I get the jeep back tomorrow, I'll know. So will they.

Lastly, so will you.
 

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Discussion Starter #8
I just picked up my LJ from ClearLake Doge Jeep.

The transmission simulator showed a faulty TRS. The TRS was replaced along with a filter and new transmission fluid. after it was replaced the temp reading were correct and the Tech was able to do a quick learn....

We will see if this repair was indeed the culprit, as opposed to a bad PCM.

As I said before, any and all issues will be document here.
 

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Discussion Starter #9
I needed to run an errand 1 hour after I wrote the above post.

No. It's not fixed. Same hard shift when cold.
 

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Discussion Starter #10
I went to an electronics store and bought the recommended (in the above thread) electronics parts cleaner and sprayed the contacts, both the male and female sides, on all 4 plugs...... bad Idea...

So now instead of just sourcing a new PCM, I also have to replace ALL 4 PLUG ENDS!!!

There is a light blue silicone latex gasket inside the female side plug ends, the spray caused them to swell and deform to the point where the would no longer fit on the PCM.....

The good news, if there is any here, is the plug ends are available as replacement parts, so I won't have to splice wiring. The ends are about $80+ dollars each, so I'll need to dump another $350 into the jeep and still wont have a good PCM, or a fix.
 

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Enough with the off topic back and forth. Consider this the only warning.
 

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I am currently trying to solve my erratic shifting along with four O2 error codes. I have disconnected the battery which helped for a couple hours, and then I found a post on purging the PCM. Over the weekend I purged my PCM by disconnecting the positive battery cable, letting it sit for 15 minutes, reconnecting positive battery cable, turn car to on position (do not turn engine on, only power), then turn the headlights on, then off, then power down car.

Since then the car is running smooth, no check engine lights either. Once the PCM relearns will it throw the codes and erratic shifts. Time will tell and i will report back here.

like you I don't want to spend $700-$900 on a used PCM, which may or may not work. If this doesn't work my next plan is to take a look at the PCM itself for anything that looks "bad".
 

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I have been thru the same think I can't remember what codes I was throwing I do remember they had to do with tranny temp. After several trips to the dealer and a new Transmission. It was covered under warranty so l let them do it even though I thought it was the PCM. I gave up on the dealer and ordered a Mopar PCM from another dealer and had a local shop flash it. I've had no problems since then all is good.
 

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After purging the PCM the Jeep ran fantastic, for four days. Then the error codes(four O2 sensors - 0032/0038/52/58) and shifting/bucking issues came back. Ugh. Oddly enough, a couple days later my gas tank was low, about 1/8th of a tank left. Error codes just vanished, shifting/bucking stopped, Jeep was driving great. I had to fill up my gas tank though, so I did. I use 87 octane from shell or Mobil. Immediately after I filled up the tank and started the Jeep the error codes reappeared, all four, and the shifting/bucking is back.

After researching car shops in my area I found one in Fairfield, CT that repairs/cleans PCMs in-house. I am going there to see if they can diagnose anything.
 

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Discussion Starter #17
After purging the PCM the Jeep ran fantastic, for four days. Then the error codes(four O2 sensors - 0032/0038/52/58) and shifting/bucking issues came back. Ugh. Oddly enough, a couple days later my gas tank was low, about 1/8th of a tank left. Error codes just vanished, shifting/bucking stopped, Jeep was driving great. I had to fill up my gas tank though, so I did. I use 87 octane from shell or Mobil. Immediately after I filled up the tank and started the Jeep the error codes reappeared, all four, and the shifting/bucking is back.

After researching car shops in my area I found one in Fairfield, CT that repairs/cleans PCMs in-house. I am going there to see if they can diagnose anything.
Please update this thread with the PCM repair, and post all of the contact info for that company...

this is exactly where I am at in my repair hunt. I want to send my PCM in for repair, but where?

I have Googled 2006 Wrangler PCM, and checked with a few of the companies, most of them had no idea of the PCM shift related issues, a few that did, I checked their BBB review.....

It's Horrific... I have noticed that the websites claim 10 years in business etc, but the BBB says in business for less than a year....

I believe they are restructured every so often to get away from the bad reviews, business practices.

thanks for your reply.
 

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Skrelnik, you don’t give your yr but if it is ’05 or ’06 check this:

If I’m not mistaken, the O2 heater circuit can show high (voltage), the 4 codes you are getting, if the ground is bad. I notice that on ‘05s all 4 O2 heater circuits ground at the bolt on the side of the block (4.0 engine). The 2 PCM grounds are at that same place as well as some other things. On my ’05 all of the several wires are crimped into 1 terminal which is bolted to the block along with the battery negative cable on a separate terminal. Be sure to check the terminal crimp to see if any of the various wires are corroded or damaged causing a bad ground.

The wiring may be similar on other yrs too…

Edit: Not a bad idea to check continuity between the PCM & O2 sensors to ground to be sure those wires are good too.
 

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Maybe a suggestion. If the Jeep is still under warranty, see if the Dealer can request a field engineer from Chrysler to come out and take a look at the Jeep.

We did this at Chevrolet. If it was one that was a problem child, that talking to the folks at Tech Assist couldn't correct, the Engineer came out. And we had em a lot when the first 700r4 tranny hit the market.

Anywho the Field guys tend to have stuff the guys at Tech Assist often don't have, info wise. And more then often they've already seen this problem and what corrects it.

Might be worth a shot.
 

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Please update this thread with the PCM repair, and post all of the contact info for that company...

this is exactly where I am at in my repair hunt. I want to send my PCM in for repair, but where?

I have Googled 2006 Wrangler PCM, and checked with a few of the companies, most of them had no idea of the PCM shift related issues, a few that did, I checked their BBB review.....

It's Horrific... I have noticed that the websites claim 10 years in business etc, but the BBB says in business for less than a year....

I believe they are restructured every so often to get away from the bad reviews, business practices.

thanks for your reply.
I have done exactly what you did and determined that 100% of these online Sellers of rebuilt/refurbished PCMs charge you a grand for a new PCM but require you to send yours in. They then do minor updates and sell your old PCM for a grand - almost like a ponzi scheme of PCMs.

Then I decided to hunt down an electrical engineer who has experience building motherboards. I found that one shop I referenced but I have not gone yet so I do not want to endorse them or give out their name yet.

RUBI 4 MY MRS mentioned the wires not being grounded properly. I did check for that but I think I am going to disengage the ground wires and then inspect the wires more closely than before. If that fails I am off to that shop I mentioned and will report feedback

thanks RUBI 4 MY MRS - I do have a 2005 so you are in the same ballpark.
 
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