[jeepgirl1975]

I've done a lot of research and apparently my 89 cherokee uses the renix system. I've been told that renix systems do not give out error codes and have no way of storing them either so codes can not even be retrieved manually. Does that mean then that if I were to pay money to a shop for a so called diagnostic service I would be wasting money. I had already had one done a while ago and it found nothing. Then again this shop has a bad rep for not doing work

 

[Jabo]

From what I have been told it is a wast to have the codes due to the fact there charging you for something that isnot there.

 

[BlueXJ]

No codes are generated and none are stored thus the shop has to have a mechanic to diagnose not a parts changing monkey. You can do as well yourself with a FSM and a $4 multimeter. Read the instructions for each thing that needs to be tested and you will find what is and what is not within tolerances and you can thus be the one who either adjusts what needs adjusting or you can replace what needs replacing.