There have been a few reports here over the years for flashing lights. Yours are solid except for traction control? I don't have U0102-00 in my book, so I'm not going to be of much help. Did she/you try to start it? If I recall correctly, in previous cases, either the module that controls the transfer case or the transfer case itself was faulty.

I'd check under the jeep for transfercase wire harness damage.

Its may be the Transfercase Control Module (TCCM) thats reporting the vault, sometimes reported as a TCM. These Jeeps have the, whats otherwise known as a TCM, imbedded within the PCM I think. The TCCM is also know as a Driveling Control Module DTCM.

 

Thanks for your quick response. She did start it yesterday and drove it maybe 3 miles. She said it wouldn’t go above 40mph. I just got home today and got in it. Started it up and nothing was out of the ordinary. Everything worked like it should and no blinking lights. Wish I had brought my scan tool from work home again to see if the code was still active. I’ll be getting under it tomorrow morning to see if I can find anything wrong with the transfer case harness. Bad thing is I hope I find a wire or something that explains why it did what it did so I can fix it

 

It was probably in one of the limp home modes. Sometimes one of the modules just needs to reset. There has been a few reports of corrosion in connectors, which can play havoc with computer systems. The TIPM is another area that can give you unexpected symptoms.

 

Got in GC today. Traction control light was flashing. Lights on terrain mode were blinking. They would blink for a bit. Then after a little bit of driving they would go out and everything seemed to fix itself. Then it would all happen again. I checked the transfer case module. With the ignition in the run position but engine off the module just clicks like you’re flipping a light switch back and forth. With the engine running it does the same thing. I unplugged the connector at the module and checked for voltage and got 11.5-10.8v on one pin and 4.2-3.6v on another. The other 2 pins had 0 to them. This is with the engine off. Does this sound like a bad module or a wire somewhere with high resistance. I’d rather not take it to a shop when it’s something I am willing to fix at the house. I’ve been a diesel mechanic for 8 years now and am comfortable about doing electrical repairs. Just don’t know much about these Jeeps to start tearing into it. I plan to bring a power probe home tomorrow and send 12v to the transfer case module and see if it clicks and stays engaged or if it does the same thing like when the connector is plugged up. If someone has ran into this problem before and have fixed it themselves or had someone fix it for them and can give me a direction of where to go from there I would greatly appreciate it. Thanks!

 

Its not that simple to troubleshoot. These auto transfer cases are a little more complicated in that the motors are PWM with a position holding brake circuit along with rotation hall effect sensors. The motor spins both ways, depending on the polarity applied. You would have to make sure the brake is released to see any movement. You are probably seeing the transfer case motor incremental sensor which will read 0.75V or 4.2V depending on the position. It will bounce around as the motor rotates. The controller provides a 5 volt reference signal. The separate position sensor will vary between 1.8V and 3.6V. The voltage feedback from the motor brake is either near 5-8V or near 0 depending on the controller wanting to rotate the motor. So if the motor is seeing 11v and the incremental sensor is not changing, it kinda sounds like the controller is trying to rotate the motor but nothing is happening.... but thats just a wild guess.

There have been a couple recent transfer case issue threads, with clicking actuators. Here is one that turned up in a search:

http://www.jeepforum.com/forum/f309/2012-laredo-5-7l-v8-transfer-case-issue-4313371/

You are really flying blind without being able to read the drivetrain control module and cabin node codes. Its the only way to efficiently troubleshoot short of replacing components on speculation. The scan tool also allows the tech to command functions so the reaction can be observed.

When you say module, do you mean the control module under the rear quarter panel trim, or the transfercase? The control module itself needs at least 8.5 volts from the battery.

You will find most of the time this kind of problem turns out to be a transfercase replacement or control module replacement or both the controller and actuator (one burns the other out). Sometimes the position sensor. Sometimes its a data bus thing, where a misbehaving module throws noise onto the data bus. Intermitents are loose or corroded connections most of the time.

I don't have a 2014 circuit diagram handy. You can get a three day pass to FCA's technical data base, which includes FSM type data and more, for around $35. They usually have pretty detailed info and info specific to the 2014.

Your symptoms are a little different in that you don't seem to have a locked up transfer case and they are intermittent... have you checked fluid levels as low fluid can cause sticky shifting? Have you tried switching between terrain modes? On second thought... that may lock you into 4WD ...

 

I cannot change modes. It’s always locked in 2wd and traction contol is always off. Occasionally it will say it’s in auto mode and traction control will go off but I still cannot change modes. I unplugged the transfer case module and it did not change anything as far as lights on the dash. I checked all the fuses and they are good. Tried to disconnect the battery and see if that would reset anything. I know that’s not a good idea but I just wanted to see if i

 

It would give me any kind of feedback. But it did not

 

Without a code reader you will be swapping parts based on speculation. Even with a code reader I hear dealers resort to swapping parts. Perhaps start with the easy stuff first, replace the actuator, replace the controller, then think about replacing the transfer case.

 

Dumb question but where is the acuator located. I located the controller which is on the bottom of the transfer case. When pulling the controller off won’t the fluid drain out of is it sealed? Don’t mean to sound stupid but I know very little about passenger cars. Thanks

 

U0102-00-LOST COMMUNICATION WITH TRANSFER CASE CONTROL MODULE / AWD

network issue -
Any other codes?
Is component currently off line or an intermittent?
......any recent work or issues?
confirm component 12v and ground,
Did you loook at freeze frsme?

 

The transfer case has a position (mode) sensor and motor (sometimes called an actuator) attached. The Drive Train Control Module (sometimes call a transfer case control module) is inside the Jeep, in the compartment under the driver's seat.

I'm guessing the Jeep PCM can't talk to the drive train/ transfer case control module for some reason, which there can be many.

 

It’s an intermittent problem. I unplugged the connector on the back of the transfer case and it set a CEL and read “service 4wd system” I did get the lights to come on the mode selector for the different terrains. I’m kinda leaning towards a transfer case control module but am going to bring my works snap on scanner home tomorrow to see if I can perform functional teats to the transmission and transfer case. Have yet to find any corrosion in those 2 connectors on the transfer case. When checking for 12v on the connectors. Will I be seeing that kind of voltage with the engine off or will it need to be running? I apologize I feel like I keep asking the same questions. If there’s anymore info you guys need just let me know. Y’all have been a huge help so far. Having someone help to point you in the general direction sometimes is a huge difference than going in blind so thank you!

 

Oh and ColdCase I looked under the driver side seat and the only module there is #3

 

The 2 modules or electronics on the transfer case. The one on the back is that the shift selector and the one on the bottom the control module?

 

The one on the back is the shift mode sensor that the controller uses to verify the transfer case does what it told it to do. The one on the bottom is the motor. Neither one is a control module. The control model is the on under the seat. Not all Jeeps have the other modules, I think one is the ELSD, forget what the other one is off hand.

You also could have a terrain swith problem (the knob). It will flash when the cabin node thinks there is a problem. But you may have more going on.

Anything stuck in one of the switches or is one sticky?

 

Jtec...that is the only code that I had when I had the scanner hooked to it. Ill have a scanner on it tomorrow evening so maybe/hopefully there’s more in it now and I’ll have some more info for y’all. Thanks

 

So I was able to get the scanner on it again today. Transmission has the U0102-00. ABS has the same U102-00. Instrument Panel Cluster has a U0114-00. Nothing is sticky on the switches or the buttons for anything. I’m ocd about that kind of stuff. Am sitting in the car now and it fixes itself after about 10 minutes of the key in the run position but engine off. I looked under the ABS section on the scanner and went to “troubleshooter” went to the U102-00 code. It says “Bus messages not recieved from the Drive Train Control Module for approximately 2 to 5 seconds.”
Possible causes:
Can bus circuits open or shorted
DTCs related to battery voltage, ignition, or vin messages
DTCM power and ground
Bcm not configured correctly
Module that set this DTC

 

It has started to fix itself more often now. Not sure why but it has. Transfer case motor does not click constantly when everything is working properly. When the traction control light comes on like (from the ABS) is when it all starts again. When that ligh comes on the auto light is lit on the mode selector as well as the red neutral light and the 4wd low light as well

 

Yeah, low battery voltage can cause a bunch of strange things. Is it a V6? Was it part of the alternator recall. Check the alternator ground strap if it has one. The lights are the Jeep telling you something is wrong, like one module or another is not talking. Check battery connections for tightness....

On the other hand the drivetrain control module could be intermittent, takes a long time to go through its startup checks... or the harness has some damage... hard to help from afar.

 

Just looked at the data and waited on it to fix itself and it finally did. Switched it to snow mode. Data says “Terrain Switch Position Request - Snow”
“T-Case Status - Auto”

Transfer case will not change to different modes no mater if the engine is running or not

 

The Transfercase doesn't know the terrain modes, just the position of its shift rail, which is either auto or 4Low or neutral. It will never match the terrain switch position. The DriveTrain control computer takes inputs from the switch and other modules and runs the transfer case motor how it sees fit. Try 4 low and see if the transfer case reports a 4Low mode.

 

So I got home. Started the Jeep GC. Waited on it to start working. Once it did. I put it into 4wd low. It went in like it should. Cycled PRND and back to park. Took it out of 4wd low. When it came out it started grinding gears. Now when I shift it to any gear it is a hard shift. Much harder than before I did the 4wd low cycle

 

Did the 4wd low cycle again. Whole lot of popping going on when shifting in and out of 4wd low

 

Are you saying the auto transmission is shifting with a clunk?

Depending how and when you shifted from 4wd low to normal, you could get some gear noise and clunking, but that should stop once you drive a little.

You probably need to have someone look at the transfer case.

 

Yes I was still in auto mode on my terrain selector. I know it locked into 4wd low cause I let it roll a little back and forth and it was obvious it was locked in. I disconnected the drive train control module last night and left it unplugged all night. Plugged it in this morning and it did it twice before leaving the house and once I backed out it the driveway it went back to working correctly and never did it again. I drove it all the way to daycare and to work this morning with no issues what so ever

 

Sometimes it takes the moon to line up just right to get it out of 4WD low. There is a shift procedure in the owner's manual that seems to work well.

Hopefully it was just a bad connection at the control module, but it could be a sticky transfer case shift mechanism, among a dozen other things, and switching in and out of 4WD loosened it up. Did you check the oil level?