1998 4.0L being swapped into 2000 2.5L - Chassis harness the same?

I am doing this swap. I know that the engine harness and computer will need to be moved. Is the chassis harness the same or do I need to transfer that as well? Is it similar enough that I could just swap a few pins?

Why? I have to ask, are you swapping to a 2.5?

I think he's swapping a 4.0 into an XJ that had a 2.5....that's how I read his question.

96XJ_4.0 said:

Why? I have to ask, are you swapping to a 2.5?

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THIS BELONGS IN MOD TECH--that way you will get the fastest and on-point responses.

I read it that he is putting a 98 4.0 into a 2000 XJ with a 2.5?

I think I read somewhere on this forum somebody said other than the computers and switching out the engine management harness it was fairly simple.

My 2000 parts catalog shows no engine-specific changes on the instrument panel wiring harness, nor on the body wiring harnesses. Looks like the engine harness is the only one you will need to change over. It may be worth your while to get an engine harness from a 4.0 2000 to use, since at least the O2 sensor harnesses changed between 98/99 and 2000. Should not cost much at a junkyard though, just a little annoying to pull.

EDIT: I'm pretty sure you can use the whole 98 engine harness and ECU together with the 98 engine, for some reason I thought you were going to try and use a 2000 4.0 ECU. You may run into trouble at C101, I don't have a 2000 FSM to look at and compare wiring pinouts on that (it's the bulkhead connector at the firewall on the driver's side.) I would bet on it working though.

Thanks for the help!

Cliff's Notes: I am putting a 1998 4.0 into a 2000 2.5L



Long Story:
I have a 1998 Cherokee 4x4 that has a good drivetrain, nice lift, etc. I bought it with a trashed body on it. I ran across a very nice 2000 Cherokee that had a locked up 2.5L for really cheap. I bought it and I am in the process of switching everything over. I figured that it would be a lot easier to swap the harnesses if required while the engine was out. If it makes any difference the 1998 is a 4x4 auto and the 2000 is a 2wd 5 speed. The engine harness also has the transmission and O2 wires on it so I would think that everything should switch over alright. Anyone else have any information to support or go against this? Also, I will be using the engine, trans, transfer case, PCM and everything from the 1998. Just to make sure - the computer in the engine bay is a PCM that controls the engine and trans not just an ECU that controls the engine? I haven't quite torn into the 1998 yet so I figured I might as well ask.



We don't have emissions here so as long as the front O2 works I am fine. I can always buy a simulator for the rear one if need be.

Hmmmm... nope, the XJ has a TCU and an ECU. Since you're swapping the transmission as well you will have to add a few bits of wiring to make the TCU under the dashboard communicate properly. If you don't want to do much wiring you may be better off swapping the dashboard wiring harness as well.

The TCU is mounted to the side of the tranny tunnel above the gas pedal, about even with the side of the steering column.

Sounds like it would probably be easier to swap the trans wiring over than the whole dash harness.