When investigating a low oil pressure complaint, which of the following should be performed first?

The first step when addressing a low oil pressure complaint should indeed be checking the crankcase oil level. This action is fundamental because low oil levels can directly lead to reduced oil pressure. If the oil level is inadequate, the oil pump may not be able to circulate sufficient oil throughout the engine, which can trigger low pressure warnings or related symptoms.

By verifying the oil level first, you can often resolve the issue with a simple addition of oil or identify a potential leak if the level is significantly low. It's a logical starting point since other diagnostic steps, such as testing for fuel contamination or verifying with a master gauge, might be unnecessary if the oil level is the root cause of the problem. Addressing this foundational check helps streamline the diagnosis process and potentially prevent further complications in the engine.