97+ aw4 to 88 ax15.. what do I do with the aw4 wiring?

[0regon]

Hi.

This might be more a question to post on Naxja but we all know how much better answers are here..

I'm doing a 97+ swap on my 88 mj 

the xj is a 98 with aw4, the mj had a stock 4.0 and ax15. 

I'm keeping the ax15.

My question is do I need to do anything with the aw4 wiring or TCM?   If I'm understanding correctly, the ECU and the TCM work independently from each other, so if I leave the TCM out will I have any trouble on the engine side?

 

Thanks

[89 MJ]

Make sure your MJ has an AX-15 first. 88s didn’t get them from the factory. 

[0regon]

On 3/21/2026 at 7:02 AM, 89 MJ said:

Make sure your MJ has an AX-15 first. 88s didn’t get them from the factory. 

Interesting. Guess the AX15 isn't stock. I'm sure it's an AX15 though. 

 

Either way I'm not going to run the AW4 and still want to know what to do with the TCM wiring.

 

 

 

[mjeff87]

I used an HO auto engine harness when I swapped a 4.0/AX15 into my then 2.5/AX5 87 MJ way back in the day.  I just disconnected the subharness that runs into the cab but had to jumper the NSS switch wiring for it to fire.  I don't remember which pins they were though.

 

edit:  found an old post of mine about the wiring...

 

"jump (or splice) the B and C pins on the NSS connector on the engine side harness (black wire and black/white tracer wire)"

Edited March 24 by mjeff87
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