Diagnostic Aids

WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. 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 low could cause this DTC to set.
A skewed sensor is the problem. See appropriate SENSOR RESISTANCE table in appropriate SENSOR OPERATING RANGE CHARTS article.
If engine has been allowed to sit overnight, the ECT and IAT temperature should be within the calculated amount.