CANADA ONLY -- ILLUMINATED MIL (NEW CALIBRATION). GMC Truck Sonoma Pickup

SUBJECT: CANADA ONLY -- ILLUMINATED MIL (NEW CALIBRATION)

MODELS: 1995 CHEVROLET AND GMC TRUCK S/T MODELS WITH 4.3L V6 ENGINE (VIN W - RPO L35)

CONDITION:

SOME CANADIAN VEHICLES BUILT FROM JANUARY, 1995 THROUGH APRIL, 1995 MAY (AFTER MILEAGE ACCUMULATION) SET SOME OBDII DIAGNOSTIC TROUBLE CODES, AND ILLUMINATE THE MIL (MALFUNCTION INDICATOR LAMP).

CAUSE:

FUEL WHICH CONTAINS AN ADDITIVE DESIGNATED AS MMT (METHYLCYCLOPENTADIENYL MANGANESE TRICARBONYL), AN OCTANE ENHANCER, MAY CONTAMINATE SOME ENGINE COMPONENTS CAUSING SOME DIAGNOSTIC TROUBLE CODES TO SET.

CORRECTION:

CANADIAN VEHICLES IDENTIFIED BY THE VIN BREAKPOINTS LISTED BELOW, BEING SERVICED FOR A ILLUMINATED MIL AND/OR STORED DIAGNOSTIC TROUBLE CODE SHOULD BE CHECKED AS TO THEIR CURRENT CALIBRATION.

DIVISION PLANT START VIN ENDING VIN

CHEVROLET LINDEN SK168174 SK226722 MORAINE S2175433 S2213899 SHREVEPORT S8192639 S8209137

GMC LINDEN SK523717 SK534128 MORAINE S2528380 S2545346 SHREVEPORT S8522798 S8526957

CANADIAN VEHICLES THAT HAVE THE OLD CALIBRATION SHOULD BE UPDATED WITH THE NEW CALIBRATION AS FOLLOWS:

TRANSMISSION OLD CALIBRATION NEW CALIBRATION

MANUAL (RPO M50) 16206790 16206789 AUTOMATIC (RPO M30) 16206791 16215623

THE NEWLY RELEASED CALIBRATIONS ALLOW DIAGNOSTIC TROUBLE CODES TO BE SET AND STORED, BUT MAY NOT ALLOW THE MIL TO BE ILLUMINATED FOR ALL DIAGNOSTIC TROUBLE CODES.

CANADIAN VEHICLES PRODUCED BEFORE AND AFTER THE VIN BREAKPOINTS IDENTIFIED ABOVE SHOULD CONTINUE TO BE SERVICED WITH CALIBRATIONS RELEASED FOR THEIR APPLICATION.

DIAGNOSTIC PROCEDURES AND TROUBLE SHOOTING FLOW CHARTS SHOULD CONTINUE TO BE USED WHEN SERVICING THE ABOVE VEHICLES WITH THE NEW CALIBRATIONS.

SERVICE INFORMATION THE ABOVE SERVICE "FLASH" CALIBRATIONS ARE AVAILABLE STARTING WITH THE MAY, 1995 CD ROM. THESE CALIBRATIONS ARE NOT AVAILABLE FROM GMSPO.

WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY USE: LABOR OPERATION: T2465 LABOR TIME: 0.6 HR.

FIGURES: 0 ATTACHMENTS: 0

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.