U0102 DTC today.

[Snow1er]

Hey so today I went to work no problem, when I got in and started the jeep I got a bunch of errors and amber warning lights. I got home and scanned the codes and only U0102 came up, Lost communication with transfer case control module.

So I see online that I should

Check battery connection
Look for blown fuses
Trace wiring from fuses to transfer case to control module.
Check to see if actual module is bad.

Is there anything else I should look for and investigate?? Do you think it would be safe to drive to work still? I doubt I'll fix it tonight unless it is something simple and I need it to get to work tomorrow..

Thanks for any advice!

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[Snow1er]

Checked battery and it is snug. I was looking over fuse box and noticed some odd stuffing. Started sucking it out with a shop vac. Does look to have come from the jeep and it also doesn't have poop. A critter must have been building a nest and shorted themselves on a wire.

Is it worth taking the top of the fuse tray off to see how big it is under there ???

 

[Snow1er]

Oh and I pulled the battery to let the jeep reset codes and it didn't come back but when I was using a code scanner I was unable to get it to clear.

 

[rharr]

The old chewed wire game, good luck......

Some insurance policies cover chewed wire repair fyi.

 

[Snow1er]

I took apart below the main fuse tray and I could not find any mice or any additional stuffing. Most everything was along the z bank wire fall. Maybe this weekend I'll take it all apart down to the ESS battery and see if anything else shows. I sprayed a bunch of repellent down there so any future work of mine will surely make my eyes burn a little just working and alot if I touch anything and then my face haha!!

 

[Snow1er]

My vehicle is a 2022 willys with almost 40k miles. I bought it used 1.5 years ago with 22k miles. Is it worth changing that battery as PM if I'm down in there already? Even with the snorkel tube and other stuff I'm getting pretty quick at getting down there...

 

[ShadowsPapa]

I'd be concerned that they actually chewed into a wire causing this. There's no way a rodent just going across those terminals will throw a code - they are all connected electrically anyway.
I suspect there's more damage somewhere, a wire that's chewed, maybe mostly or partially broken or shorting against a ground. You could connect every stud you see at that high current fuse area and nothing would happen - they all have battery power to each of them.

In short, I see nothing there that caused what you saw for errors. Even if they peed across all of those terminals, it would be messy, but not a problem to throw a code.

 

[Snow1er]

I was hoping they only nibbled a high current wire, it threw a code, and they died or scurried off. The nest had no pee or poop yet (unless it is right above the 2nd battery below the bottom of the fuse tray). I'll dig to the 2nd battery and below then but beyond visual inspection of that area I might be at my skill limit.

Another person told me since 4wd engagement is manual that there is a chance I could make a manual FAD switch and ignore the code if I can't fix it. Is that a viable option @ShadowsPapa ?

 

[ShadowsPapa]

I was hoping they only nibbled a high current wire, it threw a code, and they died or scurried off.

They could chew all they wanted on those wires and it won't throw a code, especially related to transfer case. Those are all hot all the time, so there's nothing they could do to them as far as chewing. If it was enough to short anything, it would blow a fuse.
You can hack on those wires all you want, nothing is going to happen. Those are for the EHPS, cooling fan, alternator and the aux battery connection to the bus. None are related to anything that can cause a code. You could even connect any of those studs together with a screw driver - and not see any problems. They could be stripped of insulation - no problem (as long as they don't touch a ground).

So my guess is there's a wire somewhere they you aren't seeing that got nipped on, maybe even under the PCD where the fuses are because that's where the real action is.

Not sure what manually operating the FAD, or even bypassing it, locking the axle halves together would do to resolve the problem. You don't know what effect that code would have - could be unrelated to FAD. The FAD may be working ok, but the transfer case isn't reporting it's position to the rest of the system.

Best to dig and check all other wiring, It's hard to assume anything at this point.

 

[Snow1er]

I guess I was assuming that the transfer case control module engaged the FAD when the lever was pulled (the lever is manual???). Maybe it changes the traction control setting or some braking parameters also. But if I cannot replicate the error, and cannot find the short. I was hoping by adding a manual switch to the FAD that 4wd would work out on a trail if something did go wrong and I was somewhere recovery was not an easy option.

 

[Snow1er]

Also I read in a JL forum that U0102 error had no fuses besides the taking power from the Z bus bar, and that an intermittent short could trigger that code. Otherwise if it doesn't trip I could scour each wire for resistance hoping to find a small chew. If the latter is the case I might see if insurance will cover the fix. With a full time plus job plus two gradeschool kids and no garage I might not have the time or facility to diagnose a problem that nuanced.

 

[ShadowsPapa]

Also I read in a JL forum that U0102 error had no fuses besides the taking power from the Z bus bar, and that an intermittent short could trigger that code.

A mouse on those wires won't constitute a short - because those don't power anything other than high current draws. The PDC, and thus all modules, gets power directly from the bus, not any of those cables. You can connect any of those studs together with a jumper or even a screw driver and do nothing. Turning on lights or hitting the start button twice without touching the brake pedal draws more power across those terminals than a mouse would as far as a sudden voltage drop.

The problem isn't at that high current fuse or those big cables. That has nothing to do with anything in the PDC at all

N1 goes from that cable right into the fuse panel, the PDC from the PCR and aux battery below. So even something hitting that isn't going to trigger a problem as it's at the same potential as N2 and so on.

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