Intake Air Temperature Sensor 2 Monitor

Intake Air Temperature Sensor 2 Monitor (V8 Supercharged Only)

High/Low Input Failure
These are continuous monitors. The voltage from the sensor is compared to a failure threshold defined in the software.

If the voltage is below the low threshold, then a timer starts to increment. Once this timer exceeds another threshold, then a failure flag is set and a DTC is stored.

If the voltage is over the high threshold defined in the software, then a timer starts to increment. Once this timer exceeds a threshold, then a failure flag is set and a DTC is stored.

Range/Performance Check 1
If engine speed and intake airflow is sufficient, the ECT is low enough and the air temperature sensor voltage is lower than calibrated constants, then a monitoring failure judgment is made.

If after a calibrated period has elapsed the voltage from the sensor is greater than a calibration constant then a monitoring normal judgment is made.

Range/Performance Check 2
At intervals of approximately 2 seconds, the IAT is sampled to monitor for rapid drop in air temperature. If the change in IAT (over a 6 second period) is greater than a calibration constant then a monitoring failure judgment will be made. A normal judgment is made if the change in IAT change is less than this calibrated value.

Range/Performance Check 3
The monitor examines the integrity of IAT 2 sensor, by comparing it with the temperature signal from IAT 1 sensor, during the initial engine start up period (first 60 sec). The monitor will only execute after a cold start has been detected and appropriate cold soak flag has been set. The cold soak flag is set when the absolute of value (IAT - ECT < 10 degree C), and a cold start has been initiated. Once a cold start has been identified and the monitor entry conditions are satisfied, the monitor proceeds to compare the two sensor readings. If the absolute value of IAT 2 - IAT 1 is less than the threshold then a normal counter is incremented, and upon exceeding a calibrated threshold, a normal judgment is set. If the absolute value is greater than the threshold, then a failure counter is incremented, and upon exceeding a calibrated threshold of the counter, a failure judgment is set.