1991 S-10 Code Problem

I have a 1991 s-10 4.3 that is showing code 14. I have changed the two coolant sensors and then disconnected the battery for 5 minutes. The truck is still showing code 14. When I start the truck in the morning the service engine light is not on until I have been in the vehicle for approximately 5 minutes. What else could be causing this code? Is there something I am missing?

You might check the coolant temperature wiring for a short to ground.
Just to be sure all power was cut off to reset the trouble when you disconnected the battery, did you lose the stations set on the radio?
Once a guy had his cell phone battery charger in the vehicle with the cell phone being charged. When he disconnected his battery to reset the trouble code, the cell phone battery & charger kept just enough voltage in the circuit to keep the trouble code from being reset.

I have a 1991 s-10 4.3 that is showing code 14. I have changed the two coolant sensors and then disconnected the battery for 5 minutes. The truck is still showing code 14. When I start the truck in the morning the service engine light is not on until I have been in the vehicle for approximately 5 minutes. What else could be causing this code? Is there something I am missing?

Wiring and grounds and the computer coolant sensor plug in.
Check ground wires a thermostat housing.
Make sure coolant is full and over the tempture sensor.
And also check the air intake tempture sensor.
If you have a scanner see what the engine tempt and air intake tempt sensors are reading in the computer.
On a cold start eng and air intake should read close to the same.
And last but not least make sure thermostat is reaching operating tempture.