Final answer:
A scan tool is commonly used during the Idle Relearn procedure after replacing the intake manifold gasket due to a vacuum leak to help the car's computer relearn idle conditions.
Step-by-step explanation:
After an intake manifold gasket has been replaced due to a vacuum leak, using a scan tool to complete the job is typically necessary when performing an Idle Relearn procedure or resetting any stored codes related to the manifold or engine operation. Refilling the cooling system, torquing the manifold bolts, and performing an air cleaner check are steps that generally do not require a scan tool. Instead, they require mechanical skills and tools like a torque wrench and coolant to properly finish the work on the intake manifold. The Idle Relearn procedure helps the car's computer relearn idle conditions after the engine's intake air volume has been disrupted by a repair.