I recently bought a 1991 xj Laredo with a 4.0 but i can’t figure out how the speedometer wiring works to fix it. This wouldn’t be a problem but the check engine light comes on and i can’t get it to pass smog because of that. Anyone have any diagrams or an idea on the colors and location of the wiring for it?

 

The two things may not be related. Go get your codes read for free at Autozone

 

I think this works with a 1991 to check the codes yourself.
https://www.quadratec.com/jeep_knowl...article-24.htm

 

It will show up as a 15 but the wiring from the t-case is completely gone so I’ve had to buy a new connector for the sensor but idk where the sending unit is or how the wiring runs

 

I don't recall if the 1991 is the odd combination of both mechanically driven speedo and electrical sensor, as shown here. https://i207.photobucket.com/albums/...SCN0355111.jpg

It could be as simple as the sensor needs rotated to the proper position in the housing.