Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Sierra, 2002 GMC Savana Special, 2002 GMC Savana Camper Special, and 2002 GMC Savana. 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.