Engine Controls Tests W/O Codes - Diesel: Introduction

WARNING: Ensure negative battery cables are disconnected before disconnecting engine wiring harness. The Injector Driver Module (IDM) supplies 115-volts DC into each fuel injector connected to engine wiring harness. Severe electrical shock hazard exists. DO NOT pierce wires.

NOTE: References to Econoline include Cutaway and RV Cutaway. References to Pickup include Cab & Chassis.

Before diagnosing symptoms or intermittent faults, perform self-diagnostics in SELF-DIAGNOSTICS - DIESEL article. If any Diagnostic Trouble Codes (DTCs) are present, service DTCs as necessary. Use this article to diagnose existing driveability problems when there are no DTCs present.

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

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 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 continuous memory (intermittent) DTC was present, but no problem was found during KOEO or KOER SELF-TEST.

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