I bought a used 2006 Liberty Limited 3.7 Had issues with getting it inspected because of shuddering in the transmission and it was throwing a code. Had it rebuilt. Seemed perfect. Passed inspection. After a few thousand miles it went into limp mode. P0700 and P1745(Line Pressure too high for too long) codes were coming up. The transmission shop could not figure out what was wrong. After getting further into it, it looks like the engine was replaced. Don't know what else might have been changed in the vehicle. It has an EGR valve but no plug on the harness. I spoke with a Jeep engine rebuilder and he said if it has an EGR it has the correct reluctor on the cam and that it would be a drop in. After A LOT of back and forth the transmission shop claimed that in 2006 there were 2 transmissions, both same style, but the latter version had 2 additional solenoids that reduced the line pressure. My transmission does not have the 2 additional solenoids. The harness does not have any additional plugs for those solenoids. So now with these codes coming up the ECM/TCM has counted the mileage and the number of upshifts in the transmission and put it in limp mode.

I tried a few times to reset the ECM, which happens to be aftermarket, by using the disconnect battery method which worked for short mileage but each time I tried, the mileage got shorter and shorter. I can barely get 4 miles before it goes back into limp.

Next option would be to get a scan tool that can: "Clear Variable Line Pressure (VLP) Counters", but that would be a short term fix (2,000 miles at best) and a scan tool (Snap-On Solus or ETHOS) could cost as much as $1,500.

My last attempt was to try a matched set: ECM, Wireless Control Module, Ignition Key Cylinder and Key FOBS from a 2005 which has the same transmission. The engine started for a few seconds but then died. I took the same 2005 set and put it in my 2005 Liberty 3.7 plow vehicle and it ran fine so I know it's a matched set. Don't know what other security differences there are between 2005 and 2006 that stop this from working.

I thought about buying a new preprogrammed ECM but even if it runs fine will it go into limp too?

Guys, I'm at a loss

Any ideas on how I can get this 2006 running consistently?

Thanks,

Fred

Have you tried swapping TCM's?
Not sure about gas powered Jeep Liberty's, but on our diesel powered Liberty's, with the 545RFE transmission, you can swap TCM's between 05 & 06 vehicles at will. There are no Vins or security requirements involved.

But looking at the codes below you furnished, it appears you have an internal transmission problem.
Your best bet is to find a good reputable transmission shop and let them diagnose the problem fully.
Or, purchase a good used transmission and swap it out if your transmission is found to be faulty.
Swapping PCMs does not accomplish anything and is a waste of time and effort.
You need to have it properly diagnosed first, and then decide the best course of action.
Good luck!

P1700 code (Generic Code)
The Powertrain Control Module (PCM) monitors the Transmission Control Module (TCM). The Diagnostic Trouble Code (DTC) will set when the TCM determines that is an internal transmission problem. If other DTCs are present, diagnose, and repair them first. Clear the DTC and drive the vehicle. If the P1700 returns, disassemble the transmission and inspect the Direct One-Way Clutch.

P1745 JEEP code description The P1745 code is an informational code to inform the technician that transmission has been operating in an open-loop line pressure control for 3220 kilometers (2000 miles) or 1000 2-3 upshifts resulting from a Line Pressure DTC. The Transmission is not designed to operate in open-loop line pressure control for an extended period time. This code is intended to protect the transmission. If the P1745 code sets, the transmission controller will place the transmission into limp-in mode.

Read more: https://www.autocodes.com/p1745_jeep.html

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05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Thanks for the input. I failed to mention a few more things so my apologies.

Found this info online a while ago:
"Chrysler introduced a Variable Line Pressure Solenoid to the existing 41TE (A604) and 42RLE transmission as early as 2007. The addition of this solenoid includes the use of a transducer to verify line pressure control as feedback to the computer." "It's purpose is simple, to improve fuel economy."

The transmission shop also picked up a few additional codes:
P1684 Power to PCM was interrupted, bad connection, Faulty TCM, Battery recently disconnected. (probably because the battery was recently disconnected)
P0935 Faulty Hydraulic Pressure or connection

The transmission shop has done 2 other transmissions for me in the past with no issues. They have a good reputation. They also contacted another transmission shop who could offer no advice.

It appears that the TCM is looking for information from the Variable Line Pressure Solenoid which isn't in a 2006 transmission.

Someone really screwed around with this vehicle and anything that could be done or redone is possible. One thing for sure is that the Check Engine Light is disconnected.

That's why I want to see if I can find out why the 2005 ECM/TCM/PCM, Wireless Control Module, Ignition Key Cylinder and Key FOBS won't run the vehicle. That scenario won't be looking for the VLP Solenoid which could be the simple solution. Someone must know what is different between the 2 years.

Changing the transmission now after paying almost $3,000 for the rebuild does not make sense at any point because I'm too deep into it now. Unfortunately whoever worked on this is 2 owners ago and would be the only one who knows what was done.

Thanks