Important Preliminary Inspections Before Starting
Before using the Symptom diagnosis, perform the following:
- | Ensure that the engine control module (ECM) and indicator lamp are operating correctly. |
- | Ensure that there are no diagnostic trouble codes (DTCs) that are stored. |
- | Scan tool data is within a normal operating range. |
• | 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. |
• | Locate the correct symptom. Perform the tests and inspections associated with the symptom. |
Review the system operation in order to familiarize yourself with the system functions.
Visual/Physical Inspection
Caution: Use the connector test adapter kit J 35616-A for any test that requires probing the following items:
• | The PCM harness connectors |
• | The electrical center fuse/relay cavities |
• | The component terminals |
• | The component harness connector |
Using this kit will prevent damage caused by the improper probing of connector terminals.
Several of the symptom procedures call for a careful visual and physical inspection. This can lead to correcting a condition without further tests and can save time. This inspection should include the following areas:
• | Inspect cooling system hoses and pipes for splits, kinks, and proper connections. Inspect thoroughly for any type of a leak or a restriction. |
• | Inspect for a dirty or restricted radiator and HVAC condenser. |
• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom. |
• | Inspect the surge tank reservoir for the proper coolant level. |
Identifying Intermittent Conditions
Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movement of a component. Refer to the following for a list to help determine an intermittent condition:
• | Moisture and water intrusion in connectors, terminals, and components |
• | 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 located too tight, or chaffed circuits |
• | 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 |
• | Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge |
• | Incorrect installation of non-factory, aftermarket, and after factory add on accessories |
If an intermittent is determined, refer to
Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: