OK, here's the story. Recently bought a 00 powerstroke 4x4 with a 6 speed. It has an unknown brand three positions chip on it, 240000 miles. Ran kinda rough when I got it, kinda a soft miss like a weak injector or two. So today I brought the modus scanner from the shop to see what the problem is. Got no active codes but a bunch of stored, most of which are irrelevant except.for 1212 icp not at expected and 1211 icp president above/below dsired. So I did a buzz test just in case to test the injectors and it passed. Wanted to do a contribution test so I needed to start it and warm up. Cranked several times, smoking white and tried to fire a few times. Then all of the sudden I'm cranking it and it stops. Wont crank, radio wont work, it even killed the power to the obd plug.and the scanner. All fuses seem to be OK. Unplugged batteries for an hour and no change. One other odd thing, now when I hook up the.batteries the number 1 relay in the cab clicks constantly. Its for the interior lights I think

 

sounds like you blew a fuseable link. directly off of the starter relay on the passenger fender is one. check that.

 

Turns out I'm an idiot. The battery connections looked good so I assumed they were. Corrosion where the post.and the cable ends meet was the problem. Cleaned them and it started. Got to run the contribution test and three injectors failed

 

hey that too... LOL

 

Yep that'll do it. Oh and that clicking is from the GEM being angry. They get all sorts of cranky over low voltage/bad connections at bats. Can make them even act like they're fried