Campaign: MEM-CAL Update for 1991 2WD Jimmy V6-262 43L Powertrain Management
Technical Service Bulletin # 91C126D
Date: 910701
Campaign - MEM-CAL Update
GMC NUMBER:
91-C-12
GROUP:
6D Engine Electrical
DATE:
July, 1991
SUBJECT:
IDLE SURGE/HESITATION DURING COLD START
MODELS:
1991 "T1" GMC SYCLONE (SHREVEPORT ASSEMBLY PLANT)
PAS, Inc., the final stage manufacturer of the 1991 Syclone, in consultation with General Motors, has determined that on certain 1991 GMC Syclone
trucks the Memory and Calibration units (MEM-CALs) were not optimally calibrated, resulting in an idle surge and/or hesitation condition during a
"cold" engine start.
To correct this, the MEM-CAL calibration on GMC Syclones has been changed.
VEHICLES INVOLVED Involved are CERTAIN 1991 GMC Syclones BUILT BEFORE the following VIN:
Model
Model
Year
Plant
From
Through
GMC
1991
Shreveport
SOP
M8801522
Some vehicles built before the above VIN were built with the new MEM-CAL. Those vehicles will have the following information handwritten on the
white ECM bar code label.
MEM-CAL P/N 16163961 - Broadcast AYBM
Updated (date).
The specific vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished to
all involved dealers with the campaign bulletin.
DEALER CAMPAIGN RESPONSIBILITY
Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time
forward. Dealers are to correct all affected vehicles in new and used vehicle stock prior to their sale.
Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your dealership for service in the future, you
should take the steps necessary to ensure the campaign correction has been made before reselling or releasing the vehicle.
Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer and arrangements made to make the required
correction according to instructions contained in this bulletin. It the name and address of the owner of an involved vehicle was unavailable to GMC
Truck Division at the time of campaign initiation, the dealer must determine the owner's name and address from the dealership sales records. Please
provide this information directly on the second copy of the listing next to the applicable VIN so that our records may be updated and the appropriate
notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign
envelopes.
GMC Truck Division General Motors Corporation
101 Union Street
Plymouth, Michigan 48170
OWNER NOTIFICATION
Owners will be notified of this campaign on their vehicles by GMC Truck Division (see copy of owner letter included with this bulletin). A listing of
owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing
may contain owner names and addresses obtained from State Motor Vehicle Registration records. The use of such motor vehicle registration data for any
other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to this campaign.
Service Procedure
