Symptoms Verification: Notes

Before using the Symptom tables, perform the following inspections:

• Ensure that the engine control module (ECM) and malfunction indicator lamp (MIL) are operating correctly.
• Ensure that there are no diagnostic trouble codes (DTCs) that are stored.
• Ensure that the scan tool data is within a normal operating range. Refer to Control Module References for scan tool information.
• Verify the customer concern.
• Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.