Engine Controls - Trouble Shooting - No Codes: Introduction
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. For specific testing procedures, see
SYSTEM & COMPONENT TESTING article. For specifications, see
ON-VEHICLE ADJUSTMENTS or
SERVICE & ADJUSTMENT SPECIFICATIONS article.
Before diagnosing symptoms or intermittent faults, perform steps in BASIC DIAGNOSTIC PROCEDURES and SELF-DIAGNOSTICS articles. Use this article to diagnose driveability problems when a hard fault code does not exist.
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.