SLOW CRANKING SPEED, EXTENDED CRANKING TIME, DTC P1626. GMC Truck Sonoma Pickup

SUBJECT: SLOW CRANKING SPEED, EXTENDED CRANKING TIME, DTC P1626 P1626, HARD STARTING (REPROGRAM PCM)

MODELS: 1998 CHEVROLET AND GMC "S" MODELS 1998 ISUZU HOMBRE WITH 2.2L ENGINE (VIN 4 - RPO LN2)

CONDITION:

SOME OWNERS MAY COMMENT ABOUT INTERMITTENT SLOW CRANKING SPEED AND EXTENDED CRANKING TIME OR MAY DESCRIBE THE CONDITION AS HARD STARTING. SOME OWNERS MAY ALSO COMMENT ABOUT A VEHICLE SECURITY LIGHT THAT STAYS ON THROUGH ONE KEY CYCLE AFTER AN EXTENDED CRANK EVENT.

CAUSE:

THE PCM MAY BE INDUCED TO SYNCHRONIZE INCORRECTLY DURING KEY-UP AND CRANKING. THIS WILL CAUSE SUBSEQUENT IGNITION EVENTS TO BE MIS-TIMED CREATING A SITUATION WHERE THE STARTER IS WORKING AGAINST AN IGNITION EVENT. IF THE VEHICLE IS KEYED DOWN AND ANOTHER STARTING ATTEMPT IS MADE, THE ENGINE MAY START NORMALLY.

CORRECTION:

REPROGRAM THE PCM WITH THE REVISED CALIBRATION THAT TAKES INTO ACCOUNT THE ABOVE CONDITIONS. THESE CALIBRATIONS ARE AVAILABLE ON 1998 CD-ROM 12 AND LATER VERSIONS.

SERVICE PROCEDURE:

1. IF THE CUSTOMER HAS A CONCERN WITH SLOW CRANKING OR ANY OF THE OTHER CONDITIONS NOTED ABOVE, CONNECT A TECH 2 SCAN TOOL AND NOTE THE CALIBRATION ID CURRENTLY IN THE PCM.

2. REPROGRAM THE PCM WITH THE NEW CALIBRATION NUMBER LISTED IN THE TABLE BELOW.

3. OPERATE THE VEHICLE AND CHECK FOR ANY ADDITIONAL SLOW CRANKING CONCERNS.

4. IF THE VEHICLE STILL EXHIBITS A SLOW CRANKING CONDITION, USE APPROPRIATE SERVICE MANUAL DIAGNOSTICS TO CORRECT THE CONDITION.

CALIBRATION NUMBERS:

USE THE CORRECT CALIBRATION FROM THE LIST BELOW.

CHEVROLET S10, GMC SONOMA, ISUZU HOMBRE:

ENGINE NEW OLD AND CAL BROADCAST CAL BROADCAST TRANSMISSION NUMBER CODE NUMBER CODE USAGE ------------ ------ ---- ------ ----- -----

LN2 AND 5- 9364973 CPJJ 9356823 CLZR LN2 + MW2 + GT4 SPEED MANUAL Z83/Z85 + NF2 TRANSMISSION Z89 - NN8

LN2 AND 5- 9364983 CPJK 9356833 CLZS LN2 + MW2 + GT4 SPEED MANUAL Z83/Z85 + NB6 TRANSMISSION LN2 + MW2 + GT4 Z83/Z85 + NF2 + Z89

LN2 AND 5- 9364993 CPJL 9356843 CLZT LN2 + MW2 + GT4 SPEED MANUAL Z83/Z85 + NN8 TRANSMISSION

LN2 AND 5- 9365043 CPJS 9356873 CLZX LN2 + MW2 + GT4 SPEED MANUAL ZQ8 + NF2/NB6 - TRANSMISSION NN8

LN2 AND 5- 9365003 CPJM 9356853 CLZU LN2 + MW2 + GT5 SPEED MANUAL Z83/Z85 + NF2/NB6 TRANSMISSION -NN8

LN2 AND 5- 9365013 CPJN 9356863 CLZW LN2 + MW2 + GT5 SPEED MANUAL Z83/Z85 - NN8 TRANSMISSION

LN2 AND 5- 9365053 CPJT 9356883 CLZY LN2 + MW2 + GT5 SPEED MANUAL ZQ8 + NF2/NB6 + TRANSMISSION NN8

LN2 AND 4 9365023 CPJP 9353953 CKRK LN2 + M30 + SPEED AUT0 Z83/Z85 + TRANSMISSION NF2/NB6 - NN8

LN2 AND 4 9365033 CPJR 9353963 CKRL LN2 + M30 + SPEED AUT0 Z83/Z85 + NN8 TRANSMISSION

LN2 AND 4 9365063 CPJU 9353993 CKRP LN2 + M30 + GT5 SPEED AUTO ZQ8 + NF2/NB6 + TRANSMISSION NN8

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION DESCRIPTION LABOR TIME --------------- ----------- ---------- J6355 PROM-REPROGRAMMING 0.4

* DIAGNOSIS TIME MAY BE CLAIMED FOR 0.0 TO 0.3 HOURS DEPENDING ON ACTUAL TIME PERFORMING DIAGNOSIS.

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.