What action should be performed to check for an exhaust leak inside the cab?

To check for an exhaust leak inside the cab, the best action to take is to smell for possible leaks. Exhaust leaks can release harmful gases, including carbon monoxide, which can pose serious health risks if inhaled. By smelling for fumes, you can detect the presence of exhaust gases that may have entered the cabin.

While other options could potentially help identify issues, they are not as direct or effective for identifying exhaust leaks. Listening for loud noises may indicate other mechanical issues, and opening the windows may simply provide ventilation without determining the source of the problem. Turning off the engine is a necessary step when conducting a thorough inspection, but it does not directly assist in identifying whether there is an exhaust leak present while the vehicle is in operation. Thus, being aware of the smell of exhaust fumes is the most reliable method in this scenario.