EXCHANGE PROGRAM: BI-FUEL COMPRESSED NAT. GAS MASS. GMC Truck GMC C Pickup

REVISION: 04/23/98

THIS BULLETIN IS BEING REVISED TO EXTEND THE END DATE OF THE PROGRAM AND ADD THE 1998 MODEL. PLEASE DISCARD CORPORATE BULLETIN NUMBER 76-63-08 (SECTION 6E - ENGINE FUEL & EMISSION) ______________________________________________________________________

SUBJECT: EXCHANGE PROGRAM - BI-FUEL COMPRESSED NATURAL GAS MASS SENSOR/MIXTURE CONTROL VALVE, FUEL TANK ASSEMBLY AND ENGINE CONTROL MODULE

MODELS: 1997-98 CHEVROLET AND GMC C2 PICKUP TRUCKS EQUIPPED FOR BI-FUEL OPERATION (RPO KL6)

TO PROVIDE PRODUCT FEEDBACK, A PARTS EXCHANGE PROGRAM IS BEING IMPLEMENTED FOR THE BI-FUEL COMPRESSED NATURAL GAS (CNG) FUEL TANK, MASS SENSOR/MIXTURE CONTROL VALVE AND ENGINE CONTROL MODULE. THIS EXCHANGE PROGRAM WILL END JANUARY 15,1999. THE PROGRAM IS NOT OPTIONAL. ALL OF THE ABOVE BI-FUEL COMPONENTS REQUIRING REPAIR MUST BE EXCHANGED.

IMPORTANT: EXCHANGED BI-FUEL COMPONENTS MUST NOT BE DISASSEMBLED AND MUST BE RETURNED AS A COMPLETE UNIT. DEALERSHIPS RETURNING BI-FUEL COMPONENTS EVEN PARTIALLY DISASSEMBLED, WILL BE SUBJECT TO BEING BILLED FOR THE EXCHANGE BI-FUEL COMPONENTS.

EXCHANGE PROCEDURE

1. CONTACT YOUR DIVISIONAL TECHNICAL ASSISTANCE GROUP WITH DETAILS OF THE CONCERN. TECHNICAL ASSISTANCE WILL OPEN A CASE AND CONTACT IMPCO. IMPCO MAY THEN CONTACT THE DEALERSHIP TO ASSIST IN DIAGNOSIS. IF AN EXCHANGE FUEL TANK IS DETERMINED NECESSARY, IT WILL BE SHIPPED VIA THE FASTEST AVAILABLE MEANS FROM IMPCO. EXCHANGED SENSORS AND MODULES WILL BE SHIPPED FROM A GMSPO WAREHOUSE. 2. WHEN THE EXCHANGE UNIT IS RECEIVED, THE REPLACEMENT UNIT MUST BE RETURNED TO THE GM WARRANTY PARTS CENTER UPON RECEIPT OF THE "GM PART AND/OR REPAIR ORDER RETURN REQUEST" MESSAGE VIA DCS AND WITHIN 21 DAYS TO AVOID A CHARGE-BACK. 3. REPLACEMENT BI-FUEL COMPONENTS MUST BE RETURNED COMPLETE AS REMOVED FROM THE VEHICLE. THEY MUST NOT BE DISASSEMBLED AT ANY TIME BEFORE RETURN. DEALERSHIPS RETURNING UNITS EVEN PARTIALLY DISASSEMBLED WILL BE SUBJECT TO BILLING FOR THE COMPONENT.

PREPARATION FOR SHIPPING FUEL TANK

1. VENT FUEL FROM THE FUEL TANK IN ACCORDANCE WITH ALL LOCAL, STATE AND FEDERAL REGULATIONS. 2. REMOVE ALL PLASTIC SHIPPING PLUGS AND COVERS FROM THE REPLACEMENT FUEL TANK AND INSTALL THEM ON THE REPLACED FUEL TANK. 3. PLACE A COPY OF THE REPAIR ORDER IN THE PLASTIC BAG AND ATTACH THE BAG TO THE REPLACED FUEL TANK BEING RETURNED. 4. PACK THE REPLACED FUEL TANK INTO THE ORIGINAL SHIPPING CONTAINER AND RETURN TO THE FOLLOWING ADDRESS.

GM WARRANTY PARTS CENTER 45 NORTHPOINTE DR. ORION, MI 48359

IMPORTANT: REFER TO WARRANTY ADMINISTRATION BULLETIN 40-05-01B, DATED SEPTEMBER 1997 FOR SHIPPING INSTRUCTIONS.

CNG GAS MASS SENSOR/MIXTURE CONTROL VALVES AND ENGINE CONTROL MODULES MUST ALSO BE RETURNED TO THE GM WARRANTY PARTS CENTER.

YOUR COOPERATION IS GREATLY APPRECIATED.

PARTS INFORMATION

P/N DESCRIPTION QTY 52368532 SENSOR ASM, CNG FEED FLOW 1 52368538 1997 MODULE CNG CONTROL 1 52368812 1998 MODULE CNG CONTROL 1 52368528 1997 TANK ASM, FUEL (CNG) 1 52368803 1998 TANK ASM, FUEL (CNG) 1

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO AND IMPCO.

WARRANTY INFORMATION

LABOR OP DESCRIPTION LABOR TIME OTHER LABOR HR. L1232 FUEL TANK-REPLACE USE PUBLISHED ADD 0.2 HR FOR LABOR OPERATION ADMINISTRATIVE TIME TIME J8300 MODULE, CONTROL-REPLACE

J8333 SENSOR, GAS MASS-REPLACE

IMPORTANT: LABOR OPERATION IS CODED TO BASE VEHICLE COVERAGE IN THE WARRANTY SYSTEM.

FIGURES: 00 ATTACHMENTS: 00

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.