FALSE DTC P0121 (REPROGRAM PCM). Buick Skylark 1997

REVISION: 05/05/98

THIS BULLETIN IS BEING REVISED TO ADD ADDITIONAL MODELS AND CALIBRATION NUMBERS. PLEASE DISCARD CORPORATE BULLETIN 77-65-14 (SECTION 6E - ENGINE FUEL AND EMISSION). ______________________________________________________________________ SUBJECT: FALSE DTC P0121 (REPROGRAM PCM)

MODELS: 1997 BUICK CENTURY, SKYLARK 1997 CHEVROLET LUMINA, MONTE CARLO, MALIBU, VENTURE 1997 OLDSMOBILE ACHIEVA, CUTLASS, CUTLASS SUPREME, SILHOUETTE 1997 PONTIAC GRAND AM, GRAND PRIX, TRANS SPORT WITH 3100/3400 V6 ENGINE (VINS M, E - RPOS L82, LA1)

CONDITION:

SOME OWNERS MAY EXPERIENCE A MIL (MALFUNCTION INDICATOR LAMP) LIGHT ILLUMINATED ON THE VEHICLE'S INSTRUMENT PANEL. ADDITIONALLY, THE ENGINE'S NORMAL CONTROLLED IDLE SPEED MAY BE SLIGHTLY ELEVATED WHEN THE MIL IS ILLUMINATED.

CAUSE:

THE CURRENT DTC (DIAGNOSTIC TROUBLE CODE) P0121 IS TOO SENSITIVE. THE RATIONAL CHECK THAT THE DIAGNOSTIC CALIBRATION PERFORMS HAS BEEN CHANGED. PART OF THOSE CHANGES INVOLVE ELIMINATING THE DEFAULTED HIGHER IDLE.

CORRECTION:

CHECK THE CALIBRATION IDENTIFICATION NUMBER UTILIZING A SCAN TOOL DEVICE. RE-FLASH WITH THE UPDATED CALIBRATION IF THE CURRENT CALIBRATION IS NOT ONE LISTED IN THIS BULLETIN. IF THE VEHICLE ALREADY HAS THE MOST RECENT CALIBRATION, THEN REFER TO THE APPROPRIATE SERVICE REPAIR MANUAL TO DIAGNOSE AND REPAIR FOR DTC P0121. TEST DRIVE THE VEHICLE AFTER REPAIR TO ENSURE THAT THE CONDITION HAS BEEN CORRECTED. THE NEW CALIBRATIONS ARE AVAILABLE FROM THE GM SERVICE TECHNOLOGY GROUP STARTING WITH CD NUMBER 6 FOR 1998.

IMPORTANT: DO NOT ATTEMPT TO ORDER THE CALIBRATIONS FROM GMSPO. THE CALIBRATIONS ARE PROGRAMMED INTO THE VEHICLES PCM VIA A TECHLINE TOOL DEVICE.

CALIBRATION INFORMATION

CALIBRATION NUMBER CARLINE EMISSIONS 16254334 ACHIEVA, GRAND AM, SKYLARK NATIONWIDE

16254384 CENTURY UNLEADED EXPORT

16254394 CENTURY NATIONWIDE

16258174 CUTLASS, MALIBU UNLEADED EXPORT

16258184 CUTLASS, MALIBU LEADED EXPORT

16258164 CUTLASS, MALIBU NATIONWIDE

09359774 VENTURE, SILHOUETTE, TRANS FEDERAL SPORT

09359784 VENTURE, SILHOUETTE, TRANS CALIFORNIA SPORT

09359794 VENTURE, SILHOUETTE, TRANS UNLEADED EXPORT SPORT

09359804 TRANS SPORT UNLEADED EXPORT HIGH SPEED WITH XNA TIRES

09355514 LUMINA/MONTE CARLO NATIONWIDE

09355524 LUMINA/MONTE CARLO CANADIAN/UNLEADED FUEL EXPORT

09355544 LUMINA/MONTE CARLO USA NATIONWIDE POLICE/TAXI

09355554 LUMINA/MONTE CARLO CANADIAN/UNLEADED EXPORT TAXI/POLICE

09359554 GRAND PRIX USA NATIONWIDE

09359564 GRAND PRIX UNLEADED EXPORT

09359594 CUTLASS SUPREME USA NATIONWIDE

09359604 CUTLASS SUPREME UNLEADED EXPORT

WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION DESCRIPTION TIME J6355 ON-CAR PROM USE PUBLISHED LABOR REPROGRAMMING FLASH OPERATION TIME E PROM

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.