Truck Won't Crank Over

[Bengel]

Alright here we go. I was driving down the road about 40 mph and the traction control light came on and the fan was turning on at low speeds. The truck seemed to drive ok but the fan would engage every time I slowed down. I was not able to communicate with the ECM through my Tuner to read any gauges or codes. I shut the truck down and then it wouldn't crank over.

I looked the truck over and noticed the positive cable on my passenger side battery was extremely corroded and it looked like it was even burnt or shorted out. I went and bought 2 new batteries and replaced the end on the positive cable. Went to start the truck and still nothing.

Had the truck towed and started troubleshooting. For some reason the traction control light is still on. I pulled the PCM power relay out of another truck and the starter relay with no success. I don't even here a click when I try to crank. I jumped the solenoid at the starter and it cranks. I also jumped the relay (#54 I believe) and it would crank. It seems the ground comes through the ignition to power the relay? I still can not communicate with the ECM through the obd2 port. The port powers my tuner but I can't communicate. Anyone else run into this problem? Thanks in advance!!!

 

[sideactiondiesel]

Does the vehicle get VREF to pcm? If so what is it? Would wonder if pcm power supply was getting interrupted it has a chance to do some things.... Also what does the pcm see for PRNDL ?? Some things to look at .

 

[Bengel]

I am not sure what the PCM is reading for voltage? I can not get any data out of the PCM through my *******. I was going to try putting the truck in Neutral to see if that would work but I got sidetracked with kids and didn't get a chance. Another strange thing and I am not sure if it was just coincidence or not but all this started happening when I turned my tuner on while driving. I wanted to watch my EGT's before I shut truck down so I turned the power on to my tuner then these strange things started happening.

 

[Bengel]

Here's some updates but I'm still puzzled. I can bypass the starter relay and the truck starts and runs fine. But if I try to start the truck on it own it won't even click the relay. The truck does not shift right when driving. It seems I have to let out of the throttle in order for the truck to upshift. I still have a traction control light on and the button is lit up as off (obviously I can not turn it back on). I have checked every fuse possible (I believe) and I even swapped TCM's out of another truck. The TCM had the same PN except for the last 2 digits. I am running out of ideas now. Any help?!?!?

 

[Bigboytoys]

Maybe the ignition switch

 

[Bengel]

I'm back up and running!!!! I guess I just needed an $11k SnapOn Asus scan tool. Apparently the SCT programmer wouldn't completley clear my codes. All we did was hook the snap on scanner to the truck and read the codes. I had a ton of communication codes. Then we cleared them all and the truck fired right up and drives like normal. Thanks for the help