RSO

Hello,
I was wondering if anyone could tell me why I have two (TCM) in my 1999 Cherokee XJ?
It has been like that since I bought it 8 years ago.
Just rebuilt Transmission and I have a PO700 code coming up.
One is screwed to the kick panel by the air vents and the other is loose under the steering collum.
Thank you

fb97xj1

The one under the steering column is where the factory mounted it. The other was put there by someone else.

RSO

The one under the collum is loose and is the one I can not find any mention of when I search TCM locations
the one screwed to the right of the accelerator pedal by air vents is mention all the time as the location for the TCM in forums and YouTube
both TCM have the same part number

RSO

Why would someone add in a TCM and leave the original ?
how can I confirm it was added on?

lawsoncl

What prompted the trans rebuild? Are they both plugged in somehow? Any pictures?

Is the transmission a 98+ which would normally be found on a 1999 (ie had the extra speed sensor on the front drivers side)? I'm just wondering if someone got creative trying to swap to a pre-1998 TCM after swapping transmissions. Perhaps wired in the older TCM to control the trans, and left the original connected to the data lines to avoid throwing a P0700 code due to the mismatch.

RSO

Let me do some digging and pictures
The trans would start in 2 or 3 gear
and 150k on what I believe to have been original trans
fluid was dark and some what burned and particles in the fluid
so there is only suppose to be one TCM
That is what I thought

let me get back with more information

agreen

There is only 1 TCM. Are they both plugged in?

RSO

I believe they are both plugged in but I need to do so digging to see were the wires go.
The one screwed down does have what looks like a factory plug going into it.
The loose one also has a factory plug going into it but not sure were the wires go.

Could I pull the plugs and try a continuity test. I have seen some write ups on this but not sure were to look for a description of how to.

I may not get to this until next week

Merry Christmas

awg

There a two main connectors near the dipstick, trace the harness back from there

RSO

Here is a picture of the mounted TCM This would be the original location next to air vents

This is the loose TCM under column

lawsoncl

The part number is the right one for a 99. The writing on there makes me believe both were junkyard pulls.

RSO

The Jeep was operating without check engine lights and PO700 code prior to the rebuild of transmission.
In fact started engine after rebuild put about 20 miles on Jeep, ran through emissions for tags before code popped up.
Now code will not go away, clear code and it comes right back when vehicle starts up.
I am thinking I need to unplug the loose hanging TCM as it is not correct and start with the mounted TCM and check wiring and operation.
I may need to disconnect the add on TCM also.
Does anyone have a wiring diagram for the 1999 TCM?
Thank you

RSO

Will I need to purchase a new TCM from dealer or are there other options?

fb97xj1

That P0700 just means there is a fault somewhere. Could be anything. You say both TCM are plugged in? That would mean the harness has been tampered with, and another spliced in, so who knows whats going on in there if thats the case. Lots of hack jobs out there, and most are nothing but trouble. Dont bother with another (third) TCM just yet. I would unplug one and see what happens. The TCM is like the PCM in that they do not fail often, in my experience. And no, you cannot buy one from the dealer. They have been discontinued long ago.

RSO

Great thank you I will try unplugging the loose
TCM and ho from there