Hello everyone,

For the sake of knowledge and diagnosis, I'm trying to figure out what's going on with my car right now. A new engine was fitted into my 2012 XJ 5.0 NA. The engine that was swapped into it was from a 2011 XF 5.0 NA, and the complete harness that connects the ECU, engine, and transmission from the XF was used because it came from a much lower-mileage car and was in much better condition overall. Also, it had been running perfectly before it was removed. Both my original harness and the XF harness had the same part number 8W83-12B637-AE. I assume that since they both have the same exact part number, the pinout and so on are interchangeable; however, I'm three hours from my car at the moment and unable to check this for a few days. I'm no expert by any means, and if anyone could confirm this for me, I would greatly appreciate it. Thanks, everyone!

Jacob

 

JacobG1996, the wiring harness should be just fine to use. With that being said, I would highly suggest not using the ECU though if you are thinking that. There are specific numbers in the ECU that other modules need to see in a car and simply "swapping ECUs" can cause a real nightmare. So, use the harness, but that is about all I would use.