Visual and Physical Underhood Inspection

One of the most important checks is a visual underhood inspection. This can often fix a problem. These quick tests take only a few minutes, can save you valuable time, and help you repair the problem.

All powertrain diagnoses should begin with a thorough visual inspection. Visual inspection can often lead to repair of a simple problem without use of the tables.
^ Inspect all of the vacuum hoses for being pinched, cut, disconnected, or misrouted. For example, the PCV vacuum hoses can easily be installed incorrectly.
^ Check for the correct ground connections, ground eyelets connected to the ground points, and star washers installed, if applicable.
^ Check the battery positive junction block for loose retainer nuts.
^ Inspect the other wiring in the engine compartment for good connections, burned or chafed spots, pinched wires, or harness contact with sharp edges or hot exhaust manifolds.
^ Check for open or missing fuses, and for missing or incorrectly installed relays.