Final answer:
The PCM uses IAT sensor data to adjust the engine's air-fuel mixture based on the air temperature to ensure optimal combustion, performance, and efficiency. Incorrect IAT readings can result in engine inefficiencies and damage.
Step-by-step explanation:
The PCM (Powertrain Control Module) uses information from the IAT (Intake Air Temperature) sensor to make real-time adjustments to the engine's air-fuel mixture. The IAT sensor measures the temperature of the air entering the engine's intake manifold. Cooler air is denser and contains more oxygen, which necessitates a larger fuel injection to maintain the optimal stoichiometric air-fuel ratio for combustion. Conversely, warmer air is less dense, requiring less fuel. The PCM processes this data along with added inputs from other sensors to fine-tune the injection timing and volume, ensuring peak engine performance, improved fuel efficiency, and reduced emissions.
When the IAT sensor fails or provides incorrect information, the PCM may cause the engine to run rich (too much fuel) or lean (not enough fuel), leading to issues such as rough idling, poor performance, increased emissions, and potential engine damage over time. Accurate IAT readings are crucial for the health and efficiency of an engine.