0regon Posted March 21 Share Posted March 21 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 Link to comment Share on other sites More sharing options...
89 MJ Posted March 21 Share Posted March 21 Make sure your MJ has an AX-15 first. 88s didn’t get them from the factory. Link to comment Share on other sites More sharing options...
0regon Posted March 22 Author Share Posted March 22 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. Link to comment Share on other sites More sharing options...
mjeff87 Posted March 24 Share Posted March 24 (edited) 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 add info Link to comment Share on other sites More sharing options...
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