Visual Inspection

One of the most important checks is a visual underhood inspection. This can often fix a problem. Inspect all vacuum hoses for pinches, cuts, or disconnects. Inspect all the wires in the engine compartment for good connections, burned or chaffed spots, pinched wires, or contact with sharp edges or hot exhaust manifolds. These quick tests takes only a few minutes, can save you valuable time, and help you repair the problem.

All Powertrain diagnosis should begin with a thorough visual inspection. Visual inspection can often lead to repair of a simple problem without use of the charts. An example might be an unstable idle complaint with history code P030. Visual inspection may reveal a vacuum hose disconnected or a spark plug wire disconnected or cut, ISC not connected or ISC connector not latched, or other obvious causes for an unstable idle condition.

• Inspect all vacuum hoses for being pinched, cut or disconnected. Be sure to inspect hoses that are difficult to see such as beneath the upper intake, generator, etc.
• Check for proper ground connections, ground eyelets connected to ground points, star washers installed, if applicable.
• Check both battery positive junction blocks for loose retainer nuts.
• Inspect other wiring in the engine compartment for good connections, burned or chaffed spots, pinched wires or harness contact with sharp edges or hot exhaust manifolds.
• Check for blown or missing fuses and for relays missing or installed in the wrong locations.
• Inspect plug wires for proper routing, connection, cuts, visible signs of arcing to ground.