Poor Driveability Conditions and DTC 32 Set
File In Section: 6E Engine Fuel & EmissionBulletin No.: 67-65-38A
Date: June, 1997
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)
This bulletin is being revised to add G Models. Please discard Corporate Bulletin Number 67-65-38 (Section 6E - Engine Fuel & Emission).
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:
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.
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 the table.