6.5 multiple codes.
 

So i recently purchased a 1997 chevy C2500 6.5 4L80E and I'm having some small issues. This is my first diesel truck and I purchased it as a DD and to pull a horse trailer occasionally.
First off, I have noticed that even after extended driving and idling my temp gauge never seems to get over 175, So I hooked up a scanner to find codes P0126, P0216 and P0326 so I did a live data view and found that after 30 minutes of idling and 15 minutes driving my coolant temp was only 113 degrees. Am I right to assume that one or both of the thermostats are stuck open? Also, Would the temp being that low cause the P0216 (IP Timing) because the ECM is detecting that I am never reaching operating temp so it never leaves "Cold start timing"? I tried unplugging the CTS in the crossover and the idle did rise by about 100 rpm and it seemed to run slightly better. Also, I have noticed that just cruising in 2nd or 3rd gear that if my rpms rise above 2000 it develops a bad miss that goes away under full throttle or going up hill under load. I was going to attempt a KOKO but since I cannot get my temps above 180 I have been unable to do so. As far as the P0326 goes, I will test the WG tomorrow but I am not too worried about it as I will be replacing it with a TM in the next couple weeks.
Thanks in advance!

P0126 Insufficient ECT for Stable Operation
P0216 Injection Timing Control Circuit
P0236 Turbocharger Boost System

Your dyslexia makes it tough to decipher the codes you posted(p0326 does not exist)good thing you mentioned boost.

I am guessing the the ECT is bad or aftermarket or the stats are stuck open.

AC Delco ONLY for T stats and ECT.

Timing control circuit relates to wiring for and/or the timing control stepper motor IIRC.

Racer55: Thanks for the quick reply. I have read that ACDelco is the only way to go for cooling system parts and sensors so I will replace those soon and see if that helps. As far as the stepper motor goes, how much of a PITA is that to replace?

First check the wiring-mice like to make a home under the intake.

Then check with your local diesel service shop or google stanadyne service for your area and see if you can source a stepper motor if need be.

Will do, Thank you sir.