What Can This Code Mean?

[EdHale]

I started my truck this morning in 90 degree weather and the glow plug light would not go out. I have been down this road before so I looked at the code(s) and it had two:

P0671 #1 Glow Plug - No surprise here.

P0116 Engine Coolant Temp Circuit Range/Performance Problem

What could this second one be?

I have an appointment for next week to get the glow plug replaced and whatever this second is?

Any ideas guys?

I just looked this code up on Google and found it could be a stuck open thermostat. This is a possibility since the thermostats in this truck have never been changed and it did take a 12 mile drive today in 90 degree weather, all in city traffic, for the engine temp to get up to it's normal position on the gauge. Did I just answer my own question?

[CoyleJR]

Ed your 2006 LBZ and my 06 seem to be having the same problems lately. I believe that the P0116 code was showing when my thermostats were bad and not bringing the motor up to operating temperature quick enough. I didn't write down the code but P0116 sounds like the one it was throwing.