Sep 21, 2022
For the past forever ive been having issues with my wrangler from it saying I dont have a fuse, the oil pressure gauge going up and down, to the wrangler starting up very quickly one day to nothing but cranking a few days later. I took it to a fella who ran the codes for me and he says the brain wasnt responding, so before I buy a 500$ PCM im trying to see if theres a good chance this is the case my wranglers a '03 Auto 4.0, (im also curious on it being a ecm but if im honest i dont know the difference) thanks in advance
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I'd be taking a look in the resources section and downloading the FSM - Factory service manual for your Jeep. Section 8w is the wiring diagrams.

I'd start by pulling the connectors to your's on the firewall behind the battery...and checking the pins for damage or corrosion.

You can send your PCM to @Wranglerfix for testing... Mark is awesome and the most reputable PCM source.

Note too I had a dead ODB port...turns out the pin supplying 12v to my ODB reader was easy thing to do would be say the PCM is guess is you have some simple wiring problems that might be a little complicated...but figure out, diagnose and solve.

I’m with Mac. Check every ground too. Clean and tighten. Mark is a great but don’t fire the parts cannon too fast. Them bullets is pricey and miss the target a lot.