You should calibrate the PCM's Closed-Loop parameters for vehicle cruising after initial startup.

• A. Open-Loop
• B. Closed-Loop
• C. Idle
• D. Transient Response

Answer: (B)

In cruising after startup, the engine relies on feedback from the oxygen sensors to keep fuel delivery accurate. This is Closed-Loop operation: the PCM continuously compares the actual air-fuel ratio to the target and makes small adjustments through short-term and long-term fuel trims. Calibrating these Closed-Loop parameters ensures the system responds appropriately to small changes in load, speed, and conditions, keeping the mixture near the desired value (emissions-friendly and fuel-efficient) throughout steady cruising.

Open-Loop would skip this feedback and use fixed fuel maps, which isn’t ideal once sensors are warmed up and ready to correct the mixture. Idle control focuses on keeping engine speed at or near idle, not maintaining a steady cruising AFR, and transient response deals with how quickly the engine reacts to throttle changes rather than steady-state fueling. So focusing on Closed-Loop calibration directly supports stable, efficient cruising after startup.