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.
NOTE:
Testing procedure for sensors and switches is covered in appropriate SELF-DIAGNOSTICS article.
Before diagnosing symptoms or intermittent faults, perform steps in BASIC DIAGNOSTIC PROCEDURES and SELF-DIAGNOSTICS articles. Use this article to diagnose driveability problems existing when a hard fault code is not present.
Symptom checks can direct the technician to malfunctioning components for further diagnosis. A symptom should lead to a specific component test, system test or adjustment.
Use intermittent test procedures to locate driveability problems that do not occur when the vehicle is being tested. These test procedures should also be used if a 1st trip Diagnostic Trouble Code (DTC) was present, but no problem was found during self-diagnostic testing.