P0300, P0301, P0302, P0304 MISFIRE RELATED DTCS. Chevrolet Cavalier 1996

SUBJECT: P0300, P0301, P0302, P0303, P0304 MISFIRE RELATED DTCS WITH NO DRIVEABILITY CONCERN (DIAGNOSE, REPROGRAM PCM WITH REVISED CALIBRATION)

MODELS: 1996 BUICK SKYLARK 1996 CHEVROLET CAVALIER 1996 OLDSMOBILE ACHIEVA 1996 PONTIAC GRAND AM, SUNFIRE 1996 TOYOTA CAVALIER WITH 2.4L ENGINE (VIN T - RPO LD9) AND MJ1, M13, OR MN4 TRANSMISSION

CONDITION:

SOME OWNERS MAY COMMENT ABOUT AN MIL LAMP ILLUMINATION WITH NO CUSTOMER DRIVEABILITY CONCERN. THIS CONDITION MAY BE ACCOMPANIED BY VARIOUS MISFIRE RELATED DTC'S.

CAUSE:

A CONDITION MAY OCCUR AT A COLD START, IN WHICH THE VEHICLE EXHIBITS A LIGHT, IMPERCEPTIBLE MISFIRE. THIS MISFIRE WILL OCCUR WITHIN 3 MINUTES OF A COLD START AND WILL CAUSE A MISFIRE RELATED DTC TO BE SET BUT WILL NOT CAUSE ANY DRIVEABILITY CONCERN.

CORRECTION:

DIAGNOSIS PROCEDURE -

IF THE VEHICLE EXHIBITS ANY OF THE ABOVE CONDITIONS, INSTALL AN OIL PRESSURE GAUGE CALIBRATED TO READ AT LEAST 1034KPA (150PSI) IN THE OIL PRESSURE PORT ON THE INTAKE CAMSHAFT CARRIER AND OBSERVE THE OIL PRESSURE AT 3000 RPM. THE OIL PRESSURE, EVEN IN EXTREME COLD (-18 DEG. C (0 DEG. F) SHOULD NOT EXCEED 689KPA (100 PSI). WITH THE ENGINE OIL AT OPERATING TEMPERATURE, OIL PRESSURE SHOULD NOT EXCEED 586KPA (85 PSI) AT 3000 RPM. IF THE OIL PRESSURE EXCEEDS THESE LIMITS, REPLACE THE OIL PUMP COVER ASSEMBLY PER CORPORATE SERVICE BULLETIN 77-61-09B.

REPROGRAM THE PCM WITH A REVISED CALIBRATION THAT TAKES INTO ACCOUNT THE ABOVE CONDITIONS. THESE CALIBRATIONS ARE AVAILABLE ON 1998 CD-ROM #1 AND LATER VERSIONS, AND ARE LISTED BELOW.

IMPORTANT: THESE CALIBRATIONS CORRECT MISFIRE RELATED DTC'S THAT ARE IMPERCEPTABLE TO THE CUSTOMER. MISFIRE RELATED DTC'S WITH ACCOMPANYING OWNER DRIVEABILITY CONCERNS WILL NOT BE CORRECTED WITH THESE CALIBRATION CHANGES AND MUST BE DIAGNOSED AND REPAIRED USING THE APPROPRIATE SERVICE MANUAL PROCEDURES.

CALIBRATION NUMBERS:

USE THE CORRECT CALIBRATION FROM THE LIST BELOW.

NEW CAL BCC OLD CAL BCC USAGE

PONTIAC GRAND AM, BUICK SKYLARK, OLDSMOBILE ACHIEVA. LD9 AND 5 - SPEED MANUAL NATIONWIDE 9359743 CMNP 16235223 BTSJ LD9/MJ1 NF2/NB6

LD9 AND 4 - SPEED AUTO FEDERAL TIER1 9359753 CMNR 16235233 BTSK LD9/M13 NF2 LD9 AND 4 - SPEED AUTO CALIFORNIA TLEV 9359763 CMNS 16235243 BTSL LD9/M13 NB7 PONTIAC SUNFIRE, CHEVROLET CAVALIER. LD9 AND 5 - SPEED MANUAL NATIONWIDE 9359713 CMNL 16235173 BTSB LD9/MJ1 NF2/NB6

LD9 AND 4 - SPEED AUTO FEDERAL TIER1 9359723 CMNM 16235193 BTSDLD9/MN4 NF2

LD9 AND 4 - SPEED AUTO CALIFORNIA TLEV 9359733 CMNN 16235203 BTSF LD9/MN4 NB7

WARRANTY INFORMATION:

FOR VEHICLES UNDER WARRANTY, USE:

LABOR OPERATION NUMBER DESCRIPTION LABOR TIME --------------- ----------- ----------

J6352 REPROGRAM PROM - USE PUBLISHED LABOR ON CAR OPERATION TIME

J6355 REPROGRAM PROM - USE PUBLISHED LABOR OFF CAR OPERATION TIME

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.