4.17.1 Sensor Stuck

This monitor checks that the intake air temperature (IAT) sensor is not stuck at a particular value. If the airflow into the engine exceeds a threshold for longer than a calibratable time, the Intake Air Temperature sensor reading is stored. The next time the airflow into the engine drops below a second threshold and the engine is at idle, a second timer is incremented. Once this timer reaches a pre-determined value, the Intake Air Temperature sensor reading is again stored. The high flow temperature is then subtracted from the low flow temperature and if the difference is greater than a threshold a normal judgement is made. If the difference is less than the threshold a failure will be detected.