Diagnostic Aids
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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 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 the IAT temperature should be within the calculated amount.