- Visual/Physical Underhood Inspection

Perform a careful visual and physical underhood inspection when performing any diagnostic procedure or diagnosing the cause of an emission test failure. This can often lead to repairing a problem without further steps. Use the following guidelines when performing a visual and physical inspection:

^ Inspect all of the vacuum hoses for the following conditions:

- Correct routing

- Pinches

- Cuts

- Disconnects

^ Inspect the hoses that are difficult to see beneath the air cleaner, the A/C compressor, the generator, etc.

^ Inspect all of the wires in the engine compartment for the following items:

- Proper connections

- Burned or chafed spots

- Pinched wires

- Contact with sharp edges

- Contact with hot exhaust manifolds

This visual and physical inspection is very important. Perform the inspection carefully and thoroughly.

Several of the symptom procedures call for a careful Visual/Physical. It can lead to correcting a problem without further checks and can save valuable time. This check should include the following items:

^ PCM grounds for being clean, tight, and in their proper location.

^ Vacuum hoses for splits, kinks, and proper connections, as shown on Vehicle Emission Control Information label. Check thoroughly for any type of leak or restriction.

^ Air intake ducts for collapsed or damaged areas.

^ Air leaks at throttle body mounting area, Mass Air Flow (MAF) sensor and intake manifold sealing surfaces.

^ Ignition wires for cracking, hardness, proper routing and carbon tracking.

^ Wiring for proper connections, pinches and cuts.