Diagnostic Aids

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0116 is designed to detect an ECT sensor that is skewed high.
An IAT sensor that is skewed could cause this DTC to set.
When checking the ECT sensor, the Temperature vs Resistance table should be used in order to determine if a skewed sensor is the problem. See appropriate SENSOR OPERATING RANGE CHARTS article.
If the engine has been allowed to sit overnight, the ECT and IAT temperature should be within the calculated amount.