Diagnostic Aids

WARNING: This page is about a different car, the 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, 2002 Chevrolet Monte Carlo, and 2002 Chevrolet Impala. 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.
When inspecting the ECT sensor, the Temperature-vs-Resistance table should be used in order to determine if a skewed sensor is the problem. Refer to appropriate SENSOR RESISTANCE table in 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.