Important Preliminary Inspections Before Starting
Before using this section, perform the
Diagnostic System Check - Vehicle and verify all of the following conditions:
| • | The engine control module (ECM) and the malfunction indicator lamp (MIL) are operating correctly. |
| • | Diagnostic trouble codes (DTCs) are not stored. |
| • | Verify the customer concern and locate the correct symptom. Inspect the items indicated under that symptom. |
| • | Several of the symptom procedures ask for a careful visual/physical inspection. This step is extremely important, and can lead to correcting a condition without further inspections and can save valuable time. |
| • | Verify the proper installation of any of the following non-original equipment accessories: |
| • | Non-factory installed alarm |
Visual and Physical Inspection
Inspect the following items:
| • | The control module grounds for being clean, tight, and in their proper location. |
| • | The vacuum hoses for splits, kinks, and proper connections, as shown on the Vehicle Emission Control Information label. |
| • | The wiring for the following items: |
| • | Inspect for the installation of any Power Enhancing Devices. It may be necessary to remove these items for proper diagnosis. |
| • | The following symptom tables contain groups of possible causes for each symptom. The order of these procedures is not important. If the scan tool readings do not indicate the problems, then proceed in a logical order, easiest to inspect or most likely
to cause first. In order to determine if a specific vehicle is using a particular system or component, refer to
Engine Controls Schematics for an application. |
Verify Customer's Concern
Locate the correct symptom table. Inspect the items indicated under that symptom from the following symptom tables:
