Engine Controls - Tests W/O Codes - 7.3L 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.

Before diagnosing symptoms or intermittent faults, perform SELF-DIAGNOSTICS in TESTS W/CODES - 7.3L 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 TESTS - 7.3L DIESEL article. For specifications, see ADJUSTMENTS - 7.3L DIESEL or SPECIFICATIONS - 7.3L DIESEL article.