90f250
Full Access Member
Removed gem and no difference in anything besides thankfully no door/key chime, and less lights on cluster
Pcm swap???
- Thread starter 90f250
- Start date
Removed gem and no difference in anything besides thankfully no door/key chime, and less lights on cluster
Garbage_Mechan
Garbage Mechanic
Did you ever give Jonathan at Diesel Technology of Chattanooga a call?
90f250
Full Access Member
I've been texting the number on their site, they've gotten back with me about a couple things but I've done everything they've mentioned so far as well.
Garbage_Mechan
Garbage Mechanic
Sounds like you are going to need to pin out and one out everything to figure this one out. I also learned over the years doing fleet truck work after the initial thorough look around that the sooner you bit the bullet and pulled the harness the sooner it got solved.
90f250
Full Access Member
I'm fairly certain it is in fact a wiring issue. I just dont see how the hell it just went like that.. but I'm going to figure it out. I have my dash ripped apart right now trying to trace everything
90f250
Full Access Member
Well it's been a week or so now, I cant find a single thing wrong with any wiring or other components. I went ahead and had my pcm rebuilt and guess what... NOTHING CHANGED. I'm still without wts, fuel pump, and no tach movement when cranking. I legitimately am stumped and apparently everyone else is too
greenskeeper
Full Access Member
total guess here...inertia switch ?
90f250
Full Access Member
Nope..unfortunately not. I checked it, knocked it to pop it up then switched it back down to normal. One of the many first thoughts I had. I honestly think it does have to be something extremely simple however I may be overlooking. I just cant figure out what it is(obviously)
greenskeeper
Full Access Member
Can you connect to the rebuilt PCM with a scan tool ?
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90f250
Full Access Member
I have not tried yet but judging by the service engine soon light staying on I am very doubtful. I will be trying again shortly
79jasper
Chickenhawk
Maybe you already tried, but have you disconnected the gpr, ebp sensor, and icp sensor? (I believe I remember you trying the fuel heater)
Sometimes they can short.
Sent from my SM-N960U using Tapatalk
Sometimes they can short.
Sent from my SM-N960U using Tapatalk
greenskeeper
Full Access Member
SES light should indicate a stored code. Hopefully you can connect and read the code(s)
What type of scanner do you have? Some won't work on PSD and give the impression of no communication to the PCM when in fact it's the scanner.
90f250
Full Access Member
yep tried disconnecting them all, and replaced the fuse afterward to "reset" it or whatever but still nothing
90f250
Full Access Member
according to the guy at diesel tech of chattanooga, if the ses light stays on but i dont have wts fuel pump or tach movement when cranking, its a sure sign of the computer either being fried or a bad ground, power or reference wire. this all being said, scan tool still wont connect to it. ive had a snap on solus, hp tuners, and even a special one from the ford dealership ( a buddy works there) and none will connect to it, all saying no communication. however with the snap on and the ford one i can run all the tests through the gem by bypassing the pcm, but nothing will connect with the pcm.
90f250
Full Access Member
i just got done taking all the electrical connections back apart, cleaning everything with electronic cleaner, and then putting die electric grease on them all and putting back together, just in hopes maybe something was crossing over where it shouldnt... anyway no avail still. also, according to guy at diesel tech of chattanooga, the only 2 sensors that will completely shut down the pcm like this are the exhaust back pressure sensor and the icp, both are new now as well, and still nothing. also both do have the 5 volt reference going to them. but after almost 2 months in the garage this thing is getting very frustrating
