OBD SYSTEM IMPROVEMENTS (RE-FLASH CALIBRATION). Buick LeSabre 1997

SUBJECT: ON-BOARD DIAGNOSTIC (OBD) SYSTEM IMPROVEMENTS (RE-FLASH CALIBRATION)

MODELS: 1997 BUICK LESABRE, RIVIERA 1997 OLDSMOBILE EIGHTY EIGHT 1997 PONTIAC BONNEVILLE - WITH 3800 ENGINE (VIN K - RPO L36)

- AFFECTED MODELS BUILT AFTER MAY 15, 1997 - AFFECTED MODELS BUILT PRIOR TO MAY 15, 1997 AND HAVE BEEN SUBSEQUENTLY REFLASHED IN THE FIELD - AFFECTED MODELS WITH BULLETIN 77-71-55A PERFORMED - DOES NOT INCLUDE PULL AHEAD BUICK LESABRE VINS 400044- 463322

ALTHOUGH THE SUBJECT VEHICLES HAVE BEEN CERTIFIED AS COMPLYING WITH THE APPLICABLE U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA) AND CALIFORNIA AIR RESOURCES BOARD (CARB) ON-BOARD DIAGNOSTIC (OBD) REQUIREMENTS, WE HAVE IDENTIFIED AN OBD SYSTEM IMPROVEMENT THAT SHOULD BE IMPLEMENTED WHENEVER PRACTICAL.

CONDITION:

THE POST CATALYTIC CONVERTER OXYGEN SENSOR DIAGNOSTICS FOR DIAGNOSTIC TROUBLE CODES (DTC) P0137, P0138, P0140, AND P0141 HAVE BEEN INADVERTENTLY DISABLED.

AFFECTED DIAGNOSTIC TROUBLE CODES: - DTC P0137 H02S CIRCUIT LOW VOLTAGE SENSOR2 - DTC P0138 H02S CIRCUIT HIGH VOLTAGE SENSOR2 - DTC P0140 H02S CIRCUIT INSUFFICIENT ACTIVITY - DTC P0141 H02S HEATER CIRCUIT SENSOR2

CAUSE:

DURING THE 1997 MODEL YEAR A PRODUCTION RUNNING CHANGE FOR POWERTRAIN CONTROL MODULE (PCM) CALIBRATION WAS RELEASED WITH THE POST CATALYTIC CONVERTER OYYGEN SENSOR DIAGNOSTICS INADVERTENTLY DISABLED.

CORRECTION:

USE A SCAN TOOL TO VERIFY WHAT CALIBRATION IS PROGRAMMED INTO THE VEHICLE'S PCM. IF THE IMPROVED CALIBRATION HAS NOT BEEN INSTALLED, RE-FLASH THE PCM WITH THE UPDATED CALIBRATION LISTED IN THIS BULLETIN.

CALIBRATION INFORMATION THE CALIBRATIONS LISTED ARE FLASH CALIBRATIONS AND ARE NOT AVAILABLE FROM GMSPO. THE CALIBRATIONS ARE PROGRAMMED INTO THE VEHICLES PCM VIA A TECHLINE TOOL DEVICE AND ARE AVAILABLE FROM GENERAL MOTORS SERVICE TECHNOLOGY GROUP (STG) STARTING WITH 1998 DISC 10.

MAKE/ AXLE EMISSION IMPROVED OBD MODEL RATIO STANDARDS CALIBRATION ID BUICK LESABRE 2.84 US FEDERAL 09365354 LESABRE 2.84 US CALIF 09365364 LESABRE 3.06 US FEDERAL 09365394 RIVIERA 3.05 US CALIF 09365114

OLDSMOBILE P205/P215 TIRES: EIGHTY EIGHT 2.84 US FEDERAL 09365354 EIGHTY EIGHT 2.84 US CALIF 09365364 EIGHTY EIGHT 3.06 US FEDERAL 09365394

P225 TIRES: EIGHTY EIGHT 2.84 US FEDERAL 09365374 EIGHTY EIGHT 2.84 US CALIF 09365384

PONTIAC BONNEVILLE 2.84 US FEDERAL 09365354 BONNEVILLE 2.84 US CALIF 09365364 BONNEVILLE 3.06 US FEDERAL 09365394

**IMPORTANT: IF BULLETIN 77-71-55A FOR TRANSAXLE GEAR WHINE NOISE BETWEEN 20 AND 40 MPH (32 AND 64 KM/H) HAS BEEN PERFORMED ON A PARTICULAR VEHICLE, THEN THE EXISTING CALIBRATION ID WILL BE AS SHOWN IN THE COLUMN LABELED ORIGINAL GEAR WHINE CALIBRATION. REFLASH THIS PARTICULAR VEHICLE WITH THE APPROPRIATE IMPROVED OBD CALIBRATION AS SHOWN IN THE CORRESPONDING COLUMN LABELED IMPROVED OBD GEAR WHINE CALIBRATION.

**GEAR WHINE CALIBRATION FOR BULLETIN 77-71-55A:

MAKE/ AXLE EMISSION ORIGINAL GEAR IMPROVED OBD MODEL RATIO STANDARDS WHINE CAL GEAR WHINE CAL** BUICK LESABRE 2.86 US FEDERAL 16268484 09365414** LESABRE 2.86 US CALIF 16268504 09365434** LESABRE 3.05 US FEDERAL 16268494 09365424**

OLDSMOBILE P205/P215 TIRES: EIGHTY EIGHT 2.86 US FEDERAL 16268484 09365414** EIGHTY EIGHT 2.86 US CALIF 16268504 09365434** EIGHTY EIGHT 3.05 US FEDERAL 16268494 09365424**

P225 TIRES: EIGHTY EIGHT 2.86 US FEDERAL 16268544 09365484** EIGHTY EIGHT 2.86 US CALIF 16268554 09365494**

PONTIAC BONNEVILLE 2.86 US FEDERAL 16268484 09365414** BONNEVILLE 2.86 US CALIF 16268504 09365434** BONNEVILLE 3.05 US FEDERAL 16268494 09365424**

IMPORTANT: INFORM CUSTOMERS THAT THIS WORK IS BEING PERFORMED ON THEIR VEHICLES TO IMPROVE ON-BOARD DIAGNOSTIC SYSTEM OPERATION AND DOES NOT AFFECT VEHICLE DURABILITY, RELIABILITY, OR PERFORMANCE.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

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

IMPORTANT: THIS LABOR OPERATION IS COVERED UNDER EITHER THE FEDERAL OR CALIFORNIA EMISSION CONTROL SYSTEM WARRANTY (WHICHEVER APPLIES) OR THE BUMPER-TO-BUMPER COVERAGE IN THE NEW VEHICLE LIMITED WARRANTY. THE WARRANTY WITH THE BROADEST COVERAGE APPLIES.

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.