DTC 32 AND/OR POOR DRIVEABILITY CONDITIONS. GMC Truck Jimmy

REVISION: 06/17/97

THIS BULLETIN IS BEING REVISED TO ADD G MODELS. PLEASE DISCARD CORPORATE BULLETIN 67-65-38 (SECTION 6E--ENGINE FUEL AND EMISSION). ______________________________________________________________________

SUBJECT: DTC 32 AND/OR POOR DRIVEABILITY CONDITIONS (INSTALL NEW MEMCAL AND CLEAR ALL DTCS) NON-OBDII VEHICLES ONLY

MODELS: 1995 CHEVROLET AND GMC C/K, S/T, M/L, G MODELS WITH 4.3L ENGINE (VINS Z, W - RPOS LB4, L35) AND 4L60-E AUTOMATIC TRANSMISSION (RPO M30)

CONDITION:

SOME OWNERS MAY EXPERIENCE EGR VALVE STICKING OR FOREIGN MATERIAL HOLDING THE EGR VALVE OPEN/CLOSED. THIS WILL CAUSE A DTC 32 TO BE SET, WHICH MAY BE ACCOMPANIED BY POOR DRIVEABILITY CONDITIONS SUCH AS ENGINE SURGE, ENGINE KNOCK, ENGINE STALL, ROUGH IDLE, AND/OR HARD STARTING.

CAUSE:

CARBON DEPOSITS OR FOREIGN MATERIAL AFFECTING EGR VALVE OPERATION.

CORRECTION:

RECORD STORED DTC'S, INSTALL NEW MEMCAL AND CLEAR ALL DTC'S. CHOOSE THE APPROPRIATE MEMCAL FROM THE TABLE LISTED. AFTER INSTALLING THE NEW MEMCAL, PERFORM EGR VALVE TESTS LISTED BELOW:

EGR DEBRIS PURGE AND FUNCTION CHECK:

USING A TECH I/TECH II, WITH TRANSMISSION IN PARK, AND PARKING BRAKE APPLIED. WITH ENGINE AT 1,500 RPM COMMAND THE EGR VALVE TO 100% POSITION THEN COMMAND THE EGR VALVE TO 0% POSITION WHILE MONITORING ACTUAL AND DESIRED EGR POSITION. THIS PROCEDURE IS INTENDED TO CLEAR FOREIGN MATERIAL FROM THE EGR VALVE.

DID THE EGR'S VALVE DESIRED POSITION AGREE WITH THE EGR'S ACTUAL POSITION? IF YES, THE EGR VALVE IS FUNCTIONING NORMALLY. IF NOT, REPEAT THE DEBRIS PURGE TEST. IF THE EGR'S POSITION DOES NOT AGREE, REFER TO DTC 32 SECTION OF THE DRIVEABILITY AND EMISSIONS MANUAL.

DIAGNOSE AND REPAIR ANY OTHER DTC'S THAT MAY HAVE BEEN STORED. IS THE ENGINE OPERATING NORMALLY? IF YES, PERFORM VEHICLE (EGR) ROAD TEST LISTED BELOW. IF NOT, REFER TO THE APPROPRIATE DIAGNOSTIC SECTION OF THE SERVICE MANUAL.

VEHICLE (EGR) ROAD TEST:

DURING VEHICLE ROAD TEST, AFTER INSTALLING THE NEW MEMCAL, THE TECHNICIAN MAY NOTE INCREASED EGR VALVE ACTIVITY DURING LIGHT THROTTLE MANEUVERS. THIS INCREASED EGR VALVE ACTIVITY IS DUE TO THE EGR VALVE STROKING DURING WHICH THE ACTUAL POSITION WILL MOMENTARILY EXCEED THE DESIRED POSITION. THIS IS NORMAL EGR FUNCTION WITH THIS CALIBRATION. ROAD TEST THE VEHICLE FOR REPORTED DRIVEABILITY CONCERNS AND VERIFY EGR FUNCTION. HAVE CUSTOMER CONCERNS BEEN CORRECTED? IF YES, SYSTEM IS OK; RETURN VEHICLE TO CUSTOMER. IF NOT, REFER TO THE APPROPRIATE SECTION OF THE DRIVEABILITY AND EMISSIONS MANUAL.

1995 4.3L L35/LB4 WITH LINEAR EGR VALVES ONLY --------------------------------------------- NEW BROAD- PROM CAST CODE I.D. NEW MEMCAL (PROM LABEL) (SCAN BODY STYLE USAGE AXLE P/N TOOL)

C/K TRUCK NB6 GU4 (3.08) 16239474 BWAP 9485 GU6 (3.42) C/K TRUCK NB6 GT4 (3.73) 16239472 BWAN 9475 G VAN NA5/NA6 GU6 (3.42) 16239434 BWAC 9395 NB2 GT4 (3.73) S PICKUP NF2/NB6 GU4 (3.08) 16239469 BWAM 9465 GU6 (3.42) T PICKUP NF2/NB6 GU4 (3.08) 16239467 BWAL 9455 GU6 (3.42) GT4 (3.73) S/T UTILITY NF2/NB6 ALL 16239464 BWAK 9445 M VAN NF2/NB6 GU5 (3.23) 16239462 BWAJ 9435 GU6 (3.42) GT4 (3.73) M VAN VD1 GU6 (3.42) 16239457 BWAF 9415 GT4 (3.73) L VAN NA5/NA6 GU6 (3.42) 16239459 BWAH 9425 NB2 GT4 (3.73) L VAN VD1 GU6 (3.42) 16239444 BWAD 9405 GT4 (3.73)

PARTS INFORMATION PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

LABOR OPERATION PART NUMBER MEMCAL REPLACE J6364 EGR REPLACE J6270

WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

MODEL LABOR OPERATION LABOR TIME C TRUCK MEMCAL REPLACE 0.7 HRS. S/T TRUCK MEMCAL REPLACE 0.7 HRS. M/L VAN MEMCAL REPLACE 0.7 HRS. G VAN MEMCAL REPLACE 0.7 HRS.

C TRUCK EGR REPLACE 0.3 HRS. S/T TRUCK EGR REPLACE 0.4 HRS. M/L VAN EGR REPLACE 0.5 HRS. G VAN EGR REPLACE 0.5 HRS.

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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.

DTC 32 AND/OR POOR DRIVEABILITY CONDITIONS

SUBJECT: DTC 32 AND/OR POOR DRIVEABILITY CONDITIONS (INSTALL NEW MEMCAL AND CLEAR ALL DTCS) **NON-OBDII VEHICLES ONLY**