Symptoms Diagnosis: Notes

Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC TESTING and TESTS W/CODES articles were performed before diagnosing a symptom.

NOTE: Some driveability problems may have been corrected by manufacturer with a revised computer calibration chip or computer control unit. Check with manufacturer for latest chip or computer application.

Symptom checks can direct technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component, system test, or adjustment.

Use intermittent test procedures to locate driveability problems that do not occur while vehicle is being tested. These test procedures should also be used if a soft (intermittent) trouble code was present, but no problem was found during self-diagnostic testing.

NOTE: For specific testing procedures, see SYSTEM/COMPONENT TESTS article. For specifications, see ADJUSTMENTS or SPECIFICATIONS article.