Engine Controls - Trouble Shooting - No Codes: Introduction

NOTE: Some driveability problems may have been corrected by manufacturer with a revised Powertrain Control Module (PCM). Check with manufacturer for latest PCM application.

Before diagnosing symptoms or intermittent faults, perform basic diagnostic procedures in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - EXCEPT DIESEL article, and perform QUICK TEST in SELF-DIAGNOSTICS - VILLAGER article. Use this article to diagnose driveability problems existing when a Diagnostic Trouble Code (DTC) is not present or when sent here by another article.

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

Use INTERMITTENT PROBLEM DIAGNOSIS under INTERMITTENTS to locate driveability problems that DO NOT occur when the vehicle is being tested. These test procedures should also be used if an intermittent trouble code was present, but no problem was found during self-diagnostic testing.

NOTE: For specific system or component testing procedures, see SYSTEM & COMPONENT TESTING - VILLAGER article. For specifications, see ON-VEHICLE ADJUSTMENTS - TRUCKS or SERVICE & ADJUSTMENT SPECIFICATIONS - TRUCKS article.