Having more fun with the 6.0 L. I will add my fix info to some of my problems to help others and the info I know. EGR upgrade already, oil pump upgrade, dummy plugs done. The truck stranded my brother 150 miles from home and I knew the FICM was starting to go. It would not start at all from the key. I could go under the hood and make it start by jumping the starter wire (passenger side, disconnects close to firewall by squeezing the circular connector, long wire that pulls out is then touched to the positive terminal FYI). This is when i noticed the fuel filter on top was squirting out diesel when trying to start. While driving the transmission shift randomly including to first or park at 40 mph locking the rear end for a second twice. will not go into overdrive or top gear so 60 mph is 2750 rpm.
Codes found:
P0528: Fan speed not found
P0611: FICM
P0683: glow plugs
P0700: transmission
P1000: drive more for PCM to complete diagnostics
U2023: network failure
and as always B1352: key chime (means the key is on, but truck isn't running)

Took to dealership:
FICM duh!
Fan Speed indicator
Transmission range sensor
Re-flashed the truck

I took it home cleaned all battery connections, replaced FICM, checked fan wiring, fixed fuel filter leak, found a lose connection and reset the PCM clearing DTCs. The truck started and transmission shifted normally and into high gear, but power fluctuated and relay 211 clicks a lot. After a day while the check engine light came on, blinking TOW HAUL light, and no key start. Also transmission fluid checked: full and clean still.

P0528: fan again
P0700: transmission still
U2023: network failure

Cleared DTCs and the truck started twice in a row. Relay still clicking though and P0528 and P0700 back, but U2023 code didn't pop up so that's the no start issue code.

This has now been a three week long battle and I need advice. I'm about to go check all the connections under the hood again the the tranny. Then clean every ground I can find. My research has come up with TFT sensor, transmission filter or temperature sensor, and a bad MLPS (manual lever position sensor).

 

I would focus on grounds first, starting the the battery ground terminal and connection to the frame, then chase the rest of them.

 

Chased down all the grounds I could find. The P0528 fan speed code disappeared, but nothing else changed. I found one more ground to clean then I'm going to pull the tranny pan and start looking. Anyone know a good source for a transmission speed range sensor.

 

Did you ever figure out the transmission problems and why it wouldn't start the?