Hard shifts, no 1st or OD and a check engine light

dieseljoe93 · **Posted:** Tue Aug 23, 2016 8:54 pm

another odd behavior i hope its cuz its still trying to learn, likes to stay in 3rd gear at slow speeds and rapidly shift in and out of 3rd till it just hits first gear and then screams to redline before a shift

flash7210 · **Posted:** Tue Aug 23, 2016 8:55 pm

Maybe it's the BCM, FCM, gateway module, or whatever you want to call it.
The thingy that's below the battery tray, kinda next to the AC compressor.
Those things have been known to get corroded and cause some strange problems.

flash7210 · **Posted:** Tue Aug 23, 2016 8:58 pm

dieseljoe93 wrote:

another odd behavior i hope its cuz its still trying to learn, likes to stay in 3rd gear at slow speeds and rapidly shift in and out of 3rd till it just hits first gear and then screams to redline before a shift

That's not learning behavior.
That's schizophrenia.

I don't know how to explain it.
It's either the the electronics/wiring or a bad transmission.

joe_ · **Posted:** Tue Aug 23, 2016 9:36 pm

dieseljoe93 wrote:

another odd behavior i hope its cuz its still trying to learn, likes to stay in 3rd gear at slow speeds and rapidly shift in and out of 3rd till it just hits first gear and then screams to redline before a shift

Yeah that's definitely not normal, learning or not.

dieseljoe93 · **Posted:** Tue Aug 23, 2016 9:59 pm

ugh what a nightmare

most likely selling it after i finally get it fixed i hate saying it lol

the worst part about this whole headache is finding someone has the patience and knowledge to work on it I say diesel liberty and everyone scatters. prolly woulda been done weeks ago if i had more free time

flash7210 · **Posted:** Tue Aug 23, 2016 11:36 pm

Ok. I thought some more about this and did some reading.

You said you replaced the solenoid pack and then could no longer read the temp sensor, correct?

The trans temp sensor is in the solenoid pack.
So if the problem is the temp sensor then it's either a problem with the solenoid pack or the wiring harness.
Also, apparently there are two types of solenoid packs. One with a white harness connector and one that is black. You need the white one.
If you somehow installed the wrong pack, that would explain a lot.

If the solenoid pack is correct, then make sure all the harness connectors are tight.

Also, check the FCM thingy that I posted about above.

Have you tried manually shifting it from 1-2-D?
Drive it slowly, stating in 1st, shift to 2nd at 10-15 mph, then D at 20-25 mph.
If it still acts funky the problem might be in the valve body.
Or could be the range sensor which is also in the solenoid pack.

You might also want to consider replacing the transmission wiring harness. There are several folks here who have spare parts available. Maybe try starting a new post requesting a replacement harness.

dieseljoe93 · **Posted:** Wed Aug 24, 2016 8:40 pm

Flash, when i orginally replaced the solenoid pack trans temp data worked, it was after i got a bad tcm from the dealer that it stopped working. Currently there is new good tcm on it still no trans temp data whats odd tho is it either says 1023 or 5 changes with the cycle of the ignition its also throwing the code now for intermittent temp signal.

Ill try the fcm after i finish messing around with checking my wiring again

If i warranty the solenoid pack again should i get a new trs plate?

Ill try the manually shifting test tomorrow if it dries up around here, live on a dirt road and its clean under the jeep right now lol

as for the trans harness that is gonna be the last thing i do if i need too. ive checked it so many times now and get the same results of no issues wiring wise

flash7210 · **Posted:** Wed Aug 24, 2016 11:26 pm

I don't know about the TRS plate. But it couldn't hurt and isn't expensive.
Just be sure that you get the correct solenoid pack with white connector.

joe_ · **Posted:** Thu Aug 25, 2016 1:46 am

dieseljoe93 wrote:

its also throwing the code now for intermittent temp signal.

dieseljoe93 wrote:

as for the trans harness that is gonna be the last thing i do if i need too. ive checked it so many times now and get the same results of no issues wiring wise

If it's an issue with the wiring harness, it's obviously an intermittent one; could be affected by vibration. I'd suggest moving the wiring around while checking it to see if you can get any shorts/opens to start acting up. I'd also thoroughly check the connectors at the TCM and the solenoid pack for corrosion.

dieseljoe93 · **Posted:** Thu Aug 25, 2016 6:21 pm

joe i dont think its a harness issue driving or not driving it has the same symptoms all the time. ive done so much looking over and testing the harness that by now something should be different when i ohm the harness

dieseljoe93 · **Posted:** Tue Aug 30, 2016 10:51 pm

FINALLY FIXED!!!! :-)r

Flash you ended up being right Got my hands on a used bcm ( dealer said its discontinued). Swapped it in and all problems are gone, Only put 65 miles on so far but everything is back to normal

Thanks for the help everyone.

steeler8643 · **Joined:** Sat Feb 18, 2012 4:10 pm **Posts:** 37

dieseljoe93 wrote:

FINALLY FIXED!!!! :-)r

Flash you ended up being right Got my hands on a used bcm ( dealer said its discontinued). Swapped it in and all problems are gone, Only put 65 miles on so far but everything is back to normal

Thanks for the help everyone.

Hi,
So the BCM fixed the transmission?

Thanks
Bob

ebbnflow · **Posted:** Thu Feb 02, 2017 12:29 am

I think mentioned FCM / gateway module. The one under the battery tray by headlight.

steeler8643 · **Joined:** Sat Feb 18, 2012 4:10 pm **Posts:** 37

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ebbnflow wrote:

I think mentioned FCM / gateway module. The one under the battery tray by headlight.

I looked for the FCM but couldnt find it (I also have the Pdf parts fiche for the KJ and it doesnt show any modules by the battery tray. Also I dont get any Tranny codes on my OBDII reader but that thing Bucks really hard at, i think it is, 3rd and 4th gear.

Thanks
Bob

joe_ · **Posted:** Fri Feb 03, 2017 1:02 am

The FCM is a little more forward of the battery, sort of under the fuse box. However if it's a 2006 you won't find the FCM there because IIRC they integrated it into the fuse box or something.

steeler8643 · **Joined:** Sat Feb 18, 2012 4:10 pm **Posts:** 37

joe_ wrote:

The FCM is a little more forward of the battery, sort of under the fuse box. However if it's a 2006 you won't find the FCM there because IIRC they integrated it into the fuse box or something.

Thank you. I will look when I get out of work today. Mine is a 2005.

Thanks again,
Bob

steeler8643 · **Joined:** Sat Feb 18, 2012 4:10 pm **Posts:** 37

joe_ wrote:

The FCM is a little more forward of the battery, sort of under the fuse box. However if it's a 2006 you won't find the FCM there because IIRC they integrated it into the fuse box or something.

Also, the fuse box where the FCM is located does not have a lidd on it and some of the fuses are probably corroded. I will have to go through all of them and see if anything needs to be replaced.

Bob

steeler8643 · **Joined:** Sat Feb 18, 2012 4:10 pm **Posts:** 37

joe_ wrote:

The FCM is a little more forward of the battery, sort of under the fuse box. However if it's a 2006 you won't find the FCM there because IIRC they integrated it into the fuse box or something.

I got it out and took a picture. The smaller side has no plug going into it and is all corroded. The bigger side is the one that was plugged and it looks clean. Im thinking something could get inside the box through that open plug. Ive got both plugs soaking in electronic cleaner. I hope it works. I wish i new how to post the picture i took!

joe_ · **Posted:** Fri Feb 03, 2017 9:03 pm

steeler8643 wrote:

The smaller side has no plug going into it and is all corroded.

That's normal, as far as I know.

steeler8643 wrote:

Im thinking something could get inside the box through that open plug.

I think the connector is molded around the pins so that shouldn't be an issue.

steeler8643 · **Joined:** Sat Feb 18, 2012 4:10 pm **Posts:** 37

joe_ wrote:

steeler8643 wrote:

The smaller side has no plug going into it and is all corroded.

That's normal, as far as I know.

steeler8643 wrote:

Im thinking something could get inside the box through that open plug.

I think the connector is molded around the pins so that shouldn't be an issue.

OK.....so i put it all back together and took it for a ride just now and it is still shifting hard. I guess i should try checking the BCM next?

Hard shifts, no 1st or OD and a check engine light

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