Thinking of installing a 2003 4.o to replace the 4.0 in my 2000 Grand Cherokee.
I was told they are the same engine.
Do they use the same computer and wire harness?

 

My understanding is that the Grand Cherokee (WJ) model production ran from 1999 – 2004.

Therefore the 4.0L engine should be common across the production years, as should the computer and connections.

As with any such complex a product, there are bound to have been minor changes (improvements) during the production life, but they should either not be evident to you (being some internal design change) or require some minor modification to allow the swap.

Therefore I would expect there to be no major issues taking an engine (of the same size) from any year of (WJ) production and putting it into a different year of production (newer or older).

 

The harness and computer will probably be different, so just use the '03 engine and the harness/computer that's in the '00. There may be small differences in the sensors/connectors. If needed you can install the '00's sensors/accessories into the '03 engine so everything will connect properly.