DIAGNOSTIC TROUBLE CODE 32 WHILE UNDER HEAVY LOAD. GMC Truck GMC Suburban

REVISION: 12/06/95

THIS BULLETIN IS BEING UPDATED TO ADD 1994 AUTOMATIC TRANSMISSION PART NUMBERS. ----------------------------------------------------------------------

SUBJECT: DIAGNOSTIC TROUBLE CODE 32 WHILE UNDER HEAVY LOAD (INSTALL NEW MEM-CAL)

MODELS: 1994-95 CHEVROLET AND GMC TRUCK C/K, G AND P MODELS WITH 7.4L ENGINE (VIN N - RPO L19)

CONDITION:

SOME OWNERS MAY COMMENT OF A CEL WHILE UNDER A HEAVY LOAD SUCH AS TOWING. THE ECM WILL HAVE A STORED DTC 32.

CAUSE:

UNDER CERTAIN DRIVING CONDITIONS, USUALLY WHILE TOWING, THE EGR IS COMMANDED TO CYCLE OFF AND ON RAPIDLY. THIS CAN CAUSE THE EGR TO APPEAR UNRESPONSIVE TO ECM.

CORRECTION:

THE CALIBRATION HAS BEEN CHANGED TO BECOME MORE ROBUST WITH RESPECT TO THE CONDITIONS CAUSING THE EGR TO RAPIDLY CYCLE. INSTALL THE APPROPRIATE MEM-CAL FROM THE CHARTS BELOW:

1994 MODEL YEAR BROAD- VEHICLE OLD MEM-CAL NEW CAST GVW/ MODEL SCAN ID PART# SCAN ID CODE TRANS. FUEL TYPE OTHER ---------------------------------------------------------------------- C3 9465 16220284 0285 BPRH MAN. UNLEADED 15,000 GVW 4675 (RPO C5B) ---------------------------------------------------------------------- C3 9475 16220287 0295 BPRJ MAN. UNLEADED (15,000 GVW 4685 ---------------------------------------------------------------------- C2 9475 16220287 0295 BPRJ MAN. UNLEADED (15,000 GVW K2,K3 4685 ---------------------------------------------------------------------- C2,C3 8045 16231250 1265 BSRC AUTO. UNLEADED (15,000 GVW K2,K3 ---------------------------------------------------------------------- C3 8075 16231256 1285 BSRF AUTO. UNLEADED 15,000 GVW (RPO C5B) ---------------------------------------------------------------------- G3 8045 16231250 1265 BSRC AUTO. UNLEADED G3 NOT GOVERNED ---------------------------------------------------------------------- P3 8075 16231256 1285 BSRF AUTO. UNLEADED ---------------------------------------------------------------------- C2,C3 8055 16231252 1275 BSRD AUTO. LEADED K2,K3 (EXPORT) ---------------------------------------------------------------------- P3 8035 16231248 1255 BSRB AUTO. LEADED (EXPORT) ---------------------------------------------------------------------- C2,C3 9485 16226250 6175 BRCZ MAN. LEADED K2,K3 4695 (EXPORT) 1225 ----------------------------------------------------------------------

1995 MODEL YEAR

BROAD- VEHICLE OLD MEM-CAL NEW CAST GVW/ MODEL SCAN ID PART# SCAN ID CODE TRANS. FUEL TYPE OTHER ---------------------------------------------------------------------- C3 9465 16220284 0285 BPRH MAN. UNLEADED 15,000 GVW 4675 (RPO C5B) ---------------------------------------------------------------------- C3 9475 16220287 0295 BPRJ MAN. UNLEADED (15,000 GVW 4685 ---------------------------------------------------------------------- C2 9475 16220287 0295 BPRJ MAN. UNLEADED (15,000 GVW K2,K3 4685 ---------------------------------------------------------------------- C2,C3 9495 16220290 0305 BPRK AUTO. UNLEADED K2,K3 0645 ---------------------------------------------------------------------- G3 9495 16220290 0305 BPRK AUTO. UNLEADED G3 NOT 0645 GOVERNED ---------------------------------------------------------------------- G3 9505 16220292 0315 BPRL AUTO. UNLEADED GOVERNED (RPO 9C2) ---------------------------------------------------------------------- C3 9515 16220294 0325 BPRM AUTO. UNLEADED 15,000 GVW 0655 (RPO C5B) ---------------------------------------------------------------------- P3 9515 16220294 0325 BPRM AUTO. UNLEADED 0655 ---------------------------------------------------------------------- C2,C3 9535 16225576 5575 BRCU AUTO. LEADED K2,K3 (EXPORT) ---------------------------------------------------------------------- P3 9525 16225578 5585 BRCW AUTO. LEADED 0695 (EXPORT) ---------------------------------------------------------------------- C2,C3 9485 16226250 6175 BRCZ MAN. LEADED K2,K3 4695 (EXPORT) 1225 ----------------------------------------------------------------------

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

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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.