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.

Always attempt to retrieve Powertrain Control Module (PCM) DTCs before proceeding with SYMPTOM DIAGNOSIS. If any network "U" type DTCs are present, repair prior to PCM DTCs. If PCM DTCs are retrieved, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - VILLAGER article and service DTCs as necessary. If no DTCs are present, perform SYMPTOM DIAGNOSIS under SYMPTOMS to diagnose driveability problems existing when a hard fault code is not present. If all symptom tests check okay, perform INTERMITTENT PROBLEM DIAGNOSIS under INTERMITTENTS.

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