Set Conditions

Once the vehicle is soaked for a calibrated engine off time, then driven over calibrated speed and load conditions for some calibrated time, the Powertrain Control Module (PCM) compares the ambient, engine coolant, and intake air temperature sensor values. If the ambient air and intake air temperature sensors agree with each other but engine coolant temperature does not agree with them, the ECT sensor is declared as irrational. Two Trip Fault. Three good trips to turn off the Malfunction Indicator Lamp (MIL).