Intake Manifold Tuning Valve - Diagnosis Revised

File In Section: 6E - Engine Fuel & Emission

Bulletin No.: 61-65-63

Date: January, 1997

SERVICE MANUAL UPDATE

Subject:
Sections 3A, 3B, 3D - Revised Intake Manifold Tuning Valve Diagnosis

Models:
1993-95 Chevrolet and GMC S/T, M/L Models
with 4.3L Engine (VIN W - RPO L35)

This bulletin is being issued to inform the technician of the following:

Intake Manifold Tuning Valve Circuit:

Intake Manifold Tuning Valve Diagnosis:

^ The Intake Manifold Tuning Valve Diagnosis chart for the 1995 S/T truck has been revised.

^ The Intake Manifold Tuning Valve Diagnosis chart for the 1993 and 1994 S/T truck and the 1993 through 1995 M/L van was omitted.

Technicians are instructed to update their Service Manuals as follows:

^ Replace the chart and facing page located in the 1995 S/T Truck Driveability, Emissions and Electrical Diagnosis manual Final Edition on pages 3A-62, 3A-63, 3B-40 and 3B-41 with the attached revised chart and facing page.

^ Insert the included chart and facing page into the 1993 Light Duty Truck Fuel and Emissions Service Manual between 3D-44 and 3D-45.

^ Insert the included chart and facing page into the 1994 SIT Truck Driveability and Emissions, and Electrical Diagnosis manual.

^ Insert the included chart and facing page into the 1994 M/L Van Driveability and Emissions, and Electrical Diagnosis Manual between pages 3A-44 and 3A-45.

^ Insert the included chart and facing page into the 1995 MIL Van Driveability, Emissions, and Electrical Diagnosis Manual between pages 3A-36 and 3A-37.

Technicians are instructed to use the revised chart for diagnosis.