hello all, i have a 2003 6.0 powerstroke. i went to start the truck the other morning and it wouldnt start. tried about seven times and then gave up. (lost my temper a bit and had to walk away) i had the batteries load tested last night and the guy at auto zone said they are good. i tested the FICM this morning 45V with key on and 47V cranking. i pulled the codes on my tuner (all i have to check codes) and it pulled P0603 looked into it and its a KMA code. when i try and start it up its a really slow cranking almost like my batteries are dead. i tested them myself with my meter pulling 12.5V. my mind is boggled as to what it could be. can anyone throw a few ideas my way? anyone with the same problem? i feel like im getting close to giving up on this truck sometimes. any help would be great. 2003 6.0 powerstroke with a SCT tuner

 

My bury has the same issue and its the stand pipes and dummy plugs that were the culprit on his had a high pressure oil leak
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If your batteries are good are they rated for your truck. also it could be the starter going out. if you hook your meter to your starter and check the voltage it should drop that much from what your batteries tested. The high pressure oil leak may be it mine only does it after the oil is hot. It would start fine cold.

 

high pressure oil pump had same problem on a costumers pickup it was an 05 king ranch.

 

Have you been having any other problems with it running? the motor has to spin over at or above a cetain rpm for the computer to tell it to fire, my starter is week and I have to crank it a couple times to warm it up before it will crank fast enough.

 

once its running its fine but you shut it off warm and nothing just endless crank eventually just wouldn't start at all

 

The OPs truck is an 03, it won't have STC fitting or dummy plugs. The 03 and early 04s have few problems with High pressure Oil leaks.

 

about a month back it was hard to start. thought nothing of it as it was cooler out.the only other problems that i know of its rough running for a bit till it warms up. i know i have a slight fuel leak in the fuel pressure regulator but i dont think this would cause a no start. the water pump pulley/fan pulley shattered on me and tore my belt (replaced with the thicker upgraded pulley) that was about two weeks ago. also i changed my tune around that day. killing the EGR with the tuner and and increasing the rpms for shifting. also dont know if this helps the day before it died the AC wasnt working. blowing nothing but hot air. i bought the truck used from a dealer about a year ago for 18k. just hoping i didnt get screwed here. i bought a starter and going to put it in tonight and see if this is the problem. i dont want to just start throwing parts at it as this is a expensive way to fix things. thanks for your help guys.

 

Interesting that the ac isn't working, it could b the bearings on the AC clutch, mine locked up and motor wouldn't even spin. You can loosen your belt and then spin each pulley to see if any of them are tight/ locking up/ or real loose and wobbley. If it is the AC clutch you can replace just the clutch instead of the whole thing.

 

sounds like classic AC compressor failure... Like stated, take the belt off and watch it fire right up...