Section 17 (Engine Controls - Tests W/Codes - 7.4L): Introduction: Notes

WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Suburban, 1994 GMC Rally Camper Special, and 1994 GMC Rally. However, it is still accessible from the selected car via links, so may be relevant.

Most engine control problems result from mechanical failures, poor electrical connections or damaged vacuum hoses. Before condemning the computer system, perform checks and inspections covered in appropriate BASIC TESTING article in the ENGINE PERFORMANCE section below. Failure to do so may result in lost diagnostic time.

BASIC TESTING - GASOLINE (for "C" & "K" Series)
BASIC TESTING - GASOLINE (For "G" & "P" Series)

If no faults were found while performing BASIC TESTING PROCEDURES, proceed with DIAGNOSTIC PROCEDURE. If no fault codes or only a non-running Code 12 is present and driveability problems exist, proceed to appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE section below for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). If only intermittent codes are present, see INTERMITTENTS in appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE section.