- Visual/Physical Underhood Inspection

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/physical inspection:

^ Inspect all of the vacuum hoses for correct routing, pinches, cuts, or disconnects.

^ Inspect any 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 conditions:

- burned or chafed spots

- pinched wires

- contact with sharp edges

- contact with hot exhaust manifolds

This visual/physical inspection is very important and must be done carefully and thoroughly.

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

^ The ECM grounds for being clean, tight, and in the proper location.

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

^ The air intake ducts for collapsed or damaged areas

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

^ The ignition wires for any cracking, any hardness, or any proper routing and carbon tracking.

^ Wiring for proper connections, pinches and cuts.