Check Engine Light and Code Reader.
 

Woke up this morning, started the truck and everything was normal, heard the ding ding (which always makes my day) and my check engine light stayed on :(. Drove normal to work but stayed on. I have no idea what it could be. I am going to check all the battery cables, and fluids. Last time I took it in they found nothing but now I am at 38k, I hope it is under the 100k warranty.
My question (besides if you know what the problem could be):
IS there a cheap code reader that is reliable? Thanks for the help.
I cannot wait to take it to the shop. [dummy][duhhh][nonono]

Wife had a problem with her car (gasser) took it down to autozone and they read the codes for free, might want to give them a call and see if they can read obdII with a diesel engine.

I just checked it a code reader and it is P0514. Any suggestions would be awesome and thanks again for all your help, I cannot thank all of you enough.

P0514-BAT TEMPERATURE SENSOR RATIONALITY

Not sure why but that is that the code is saying.

This is what I found, I hope it helps others:

Last year it tossed this code. Solution pull: the drivers side battery out. Bottom of the tray will be coated with crap from road spray. Under tray the sensor twist out and is held in contact with the bottom of the battery (don't loose it) by a wavy washer. Clean tray, sensor and battery. Apply dielectric silicone grease to electrical connector and battery posts. After 40 keyed starts my 0514 code disappeared and never came back.

In addition to this, I have read that this has happened when you plug your truck in at night, and my truck was plugged in last night.