How To Use This Section

Use this portion of article only AFTER performing these checks:

Perform ON-BOARD DIAGNOSTIC SYSTEM CHECK in BASIC TESTING - TRUCKS article.
Ensure PCM and MIL function properly.
Ensure no trouble codes (except intermittent) are stored.
Ensure fuel control system operates properly. Perform FIELD SERVICE MODE CHECK in BASIC TESTING - TRUCKS article.
Perform fuel system pressure test.
Visually inspect all systems.

After performing these checks, verify customer complaint and locate correct symptom as listed in this article. Not all items listed under each symptom apply to all models and systems. These procedures normally recommend testing of a specific system or component, such as EGR, EST, TCC, etc. See SYSTEM/COMPONENT TESTS - TRUCKS article.

NOTE: If PCM displays data but engine fails to start, see NO-START DIAGNOSIS in BASIC TESTING - TRUCKS article.