Circuit/System Description

The actual throttle position and airflow rate is compared to an expected throttle position and airflow rate based on engine load. The engine control module (ECM) determines engine load based on inputs from the mass air flow (MAF) sensor and the manifold absolute pressure (MAP) sensor. Further comparisons are done to distinguish if a sensor is at fault, and the respective DTC will set.

The ECM uses the following information to calculate an expected airflow rate:

• The throttle position (TP)
• The barometric pressure (BARO)
• The MAP
• The intake air temperature (IAT)
• The engine RPM