Before calibrating idle speed control, make base calibration adjustments.

• A. Make Base Calibration Adjustments
• B. Perform Fuel Pressure Check
• C. Reset The PCM
• D. Inspect Wiring

Answer: (A)

Establishing a solid base calibration is essential when tuning idle speed control. The idle control system adjusts engine idle by adding or removing air and fuel based on sensor inputs and ECU maps, and it relies on accurate baseline engine data. If the base calibration isn’t set correctly first, the idle adjustments will be chasing incorrect targets, leading to unstable idle, surges, or stalls. By aligning base calibration—fuel maps, timing, and airflow characteristics—you give the ECU a correct reference point to fine-tune idle, making the idle behavior predictable and easier to dial in. Other checks like fuel pressure or wiring are important but don’t establish that baseline. Resetting the PCM would erase learned adjustments, which is not desirable before proper calibration.