I have a 2000 Jeep Grand Cherokee Laredo that I can not get to start, replaced ignition switch, replaced pcm, replaced several other things and cant figure it out to save my life, the key light on the dash stays on and after a few seconds the check engine light comes on but when hooked the computer to check codes it will not link up. Any help would be appreciated because i,ve almost given up hope

 

Try a different scanner.... My guess not knowing what motor you have, is to check the Crank sensor.

 

Suggestion that is free...Clean the battery terminals...good and shiny, and the ground connections. No clue where they all are on the Grand. You try posting the the Grand Cherokee forum, and might get more info than the Cherokee forum...