I have a 2000 Jeep Grand Cherokee Laredo, 4.0 I6. I am having electrical issues and the vehicle will not start. Most people with the electrical issue comment on haywire gauges and flashing lights. I have none of these symptoms. I do have the Crank, no start issue. The immobilizer light is also illuminated.

Car was operating as normal. Went to restart, car will crank, no start. Gauges are dead, instrument cluster lights illuminate. Sentry key light is on. Replaced immobilizer, reprogrammed keys, no start.
Fuel pump gets no power. No spark. Through the ASD, I can jump the fuel pump, but still no spark. Replaced crank sensor.

Now, cannot access PCM to pull codes. Scan tool powers on, but advises of linking error. I do not believe the PCM is bad as all other functions are normal.

What would cause the Sentry key light to illuminate. Would it be the passenger door switch?

 

I don't think the door switches have anything to do with the Sentry Key light illuminating. You may have a bad PCM if it's not showing any codes. The radio, HVAC controls, etc. are their own separate modules NOT connected to the PCM, if that's what you mean by everything is working. If you can, unplug/remove your PCM and take it to a shop that can do testing to see if there's a problem. Hope you're able to solve your issue.

-Vince

 

You may resolve the matter by removing battery negative then simply cycling each of the connections at the PCM. I went through the exercise on this and sprayed each connector with contact cleaner along the way, allowing chemical evaporation/dry-time before carefully reconnecting each. Additionally, I used the dry-time to remove and clean every engine compartment electrical ground point (using the FSM as my guide). I cannot be absolutely certain but somehow in the course of ground clean-ups, cable flexing and connector demates/remates a critical circuit contact issue was resolved. The problem has not recurred since - of course I expect it may happen again due to the age of my vehicle (also 18yo like yours) - but at least I'll have a clue as-to what to try before throwing money at it.