Section 78 (Engine Controls - Basic Engine Testing - 6.5L Turbo Diesel): Summary
WARNING: This page is about a different car, the 1998 GMC Forward Control and 1998 Chevrolet Forward Control. However, it is still accessible from the selected car via links, so may be relevant.
If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, no trouble codes (or only intermittent ones) were found while performing ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK and driveability problems exist, proceed to TESTS W/O CODES - 6.5L TURBO DIESEL article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.) or intermittent diagnostic procedures.