NOX CALIFORNIA EMISSIONS INSTALL NEW PROM

MODELS: 1983 S15 PICKUP EQUIPPED WITH 2.8L ENGINE (RPO LR2, VIN CODE B) AND CALIFORNIA EMISSIONS (RPO NB2)

General Motors has determined that some 1983 GMC S15 pickup model vehicles may be emitting pollutants in excess of allowable standards. Involved vehicles may not pass the NOx (oxides of nitrogen) emission standard for the state of California.

To correct this condition, a new PROM will be installed on all involved vehicles. Additionally, the primary and secondary vacuum breaks will be inspected for proper operation.

VEHICLES INVOLVED

Involved are certain 1983 GMC S15 pickup model vehicles equipped with a 2.8L engine (RPO LR2, VIN Code B) and California emissions (RPO NB2) produced within the following VIN breakpoints:

Plant From Through ----- ---- ------- Shreveport SOP EOP

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.

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.

If no owner's name and address were available to GMC Truck Division at the time of campaign initiation, the dealer will 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

I. Install new engine calibration PROM per applicable Service instructions, Manual Section 6E.

A. With automatic transmission use P/N 1228652 PROM.

B. With manual transmission use P/N 1228653 PROM.

II.Inspect vacuum breaks. Reference Truck Service Bulletin 85-B-64 (copy attached), for proper inspection procedure. Reference applicable Service Manual, if replacement is required, for service instructions and proper specifications.

PARTS INFORMATION

Parts are to be obtained from General Motors Service Parts Operation (GMSPO). To ensure that these parts will be obtained as soon as possible, they should be ordered from GMSPO on a C.I.O. order with no special instruction code, but order on an advise code (2).

PART NUMBER DESCRIPTION QTY/VEH. ------ ----------- -------- 1228652 PROM - With Auto. 1 Transmission 1228653 PROM - With Manual 1 Transmission 17078122* Vacuum Break (Primary) - l(AR) With A/C 17078531* Vacuum Break (Primary) - 1 (AR) Without A/C 17067585* Vacuum Break (Secondary) - 1 (AR) All

*It is estimated that only a small number of primary and/or secondary vacuum breaks will require replacement. Order parts accordingly, based on attached involved vehicle listing. This campaign includes a total of approximately 2885 GMC units.

To ensure parts availability upon initial owner request for vehicle correction, involved dealers are encouraged to order some quantity of parts upon receipt of this bulletin.

WARRANTY INFORMATION

Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed under this campaign.

LABOR OPERATION *TIME TROUBLE NUMBER DESCRIPTION ALLOWANCE CODE

V4360 Replace PROM .9 Hr 96 - Inspect Only - Primary - Inspect Only - Secondary V4361 Replace PROM 1.4 Hrs 96 - Inspect Only - Primary - Inspect/Replace - Secondary V4362 Replace PROM 1.4 Hrs 96 - Inspect/Replace - Primary - Inspect Only - Secondary V4363 Replace PROM 1.2 Hrs 96 - Inspect/Replace - Primary - Inspect/Replace - Secondary

* For dealer to receive Administrative Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.

CAMPAIGN IDENTIFICATION LABEL

Each vehicle corrected in accordance with the instructions outlined in this product campaign bulletin will require a "Campaign Identification Label". Each label provides a space to include the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or ball point pen.

Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner.

Apply "Campaign Identification Label" only on a clean dry surface.

ADMINISTRATIVE PROCEDURE

Procedures covering this campaign are out- lined in Section V of your dealership's "GMC Truck Claims Processing Manual" #P 8719.

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.