Symptoms Verification: Notes

Before using the Symptom tables, perform the following inspections:

• Verify that the malfunction indicator lamp (MIL) is operating correctly. Use the scan tool to command the lamp ON and OFF.
• Verify that there are no DTCs stored.
• Verify that the scan tool data is within the normal operating range. Refer to Control Module References for scan tool information.
• Verify that there are no Bulletins concerning the current symptom.
• Verify that the vehicle tires are correctly inflated and meet original equipment specifications.
• 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.

Identifying Intermittent Conditions 

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movements of a component. Refer to the following for a list of issues that may cause an intermittent condition:

• Moisture and water intrusion in connectors, terminals and components
• Incomplete connector mating
• Poor terminal contact
• High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
• Harness that is too short or tight
• Wire insulation that is chaffed or cut
• High or low ambient temperature
• High or low engine coolant temperatures
• High underhood temperatures
• Heat build up in component or circuit due to circuit resistance, poor terminal contact or high electrical load
• High or low system voltage
• High vehicle load conditions
• Rough road surfaces
• Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
• Incorrect installation of aftermarket, add on accessories