CAMPAIGN:VEHICLE CONTROL MODULE (VCM) CALIBRATION

SUBJECT: VEHICLE CONTROL MODULE (VCM) CALIBRATION

MODELS: 1996 SONOMA/S 10 TWO-WHEEL DRIVE PICKUPS EQUIPPED WITH 4.3L ENGINE (LF6) AND 5-SPEED TRANSMISSION (M50) BUILT AT LINDEN ASSEMBLY PLANT

General Motors has decided that certain 1996 Sonoma/S 10 two-wheel drive Pickup Trucks equipped with 4.3L engine (LF6) and manual 5 speed transmission (M50), built at the Linden Assembly plant, may an have incorrectly programmed Vehicle Control Modules (VCM) for engine calibration. There are two possible programming errors. First, some vehicles intended for U.S. and export sale (engine calibration P/N 16232334) may have engine calibrations (P/N 16232335) intended for vehicles sold in Canada. Second, some of these two-wheel drive pickups intended for sale in Canada (P/N 16232335) may have engine calibrations (P/N 16232336) intended for four- wheel drive pickups sold in the U.S.

To correct this condition, dealers are to reprogram the vehicle VCM with the correct data files.

VEHICLES INVOLVED

Involved are CERTAIN 1996 Sonoma/S 10 two-wheel drive Pickup Trucks equipped with 4.3L engine (LF6) and manual 5 speed transmission (M50) and built at the Linden Assembly plant within the following VIN breakpoints:

PLANT YEAR DIVISION MODEL PLANT CODE FROM THROUGH ---- ------- ----- ----- ----- ---- -------

1996 GMC S Linden K TK503275 TK524862

1996 Chevrolet S Linden K TK109943 TK212884

NOTICE: Dealers should confirm vehicle eligibility through VISS (Vehicle Information Service System) or ServiceNet (GMC only) prior to beginning campaign repairs. [Not all vehicles within the above breakpoints may be involved]

Involved vehicles have been identified by Vehicle Identification Number. Computer listings containing the complete Vehicle Identification Number, customer name and address data have been prepared, and are being furnished to involved dealers with the campaign bulletin. The Customer name and address data furnished will enable dealers to follow-up with customers involved in this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned.

These dealer listings may contain customer 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 the follow-up necessary to complete this campaign.

PARTS INFORMATION

NO PARTS ARE REQUIRED FOR THIS CAMPAIGN.

CUSTOMER NOTIFICATION

Customers will be notified of this campaign on their vehicles by General Motors (see copy of divisional customer letter included with this bulletin).

In order to ensure full protection under the emission warranty, and the right to participate in future recall, the customer notification letter recommends that customers have their vehicles serviced as soon as possible. It also advises that failure to do so could legally be determined to be lack of proper maintenance, and that the vehicle may fail a state or local emission inspection test if the recall work is not completed.

DEALER CAMPAIGN RESPONSIBILITY

All unsold new vehicles in dealers' possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before customers take possession of these vehicles.

Dealers are to service all vehicles subject to this campaign at no charge to customers, regardless of mileage, age of vehicle, or ownership, from this time forward.

Customers who have recently purchased vehicles sold from your vehicle inventory, and for which there is no customer information indicated on the dealer listing, are to be contacted by the dealer. Arrangements are to be made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such customers a copy of the appropriate divisional customer letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the customer may not as yet have received the notification letter.

In summary, whenever a vehicle subject to this campaign enters your vehicle inventory, or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle.

When a California emissions campaign is completed by a GM dealer, the dealer must provide the vehicle owner a "Proof Of Correction Certificate" which the owner may need to present to the California Department Of Motor Vehicles (DMV) when renewing their vehicle registration. Without this correction certificate, the owner may be unable to renew their vehicle registration.

Additional Certificates can be obtained, at no charge, from VISPAC, Incorporated by calling 1-800-269-5100, Monday through Friday, 8:00 A.M. to 4:30 P.M. Eastern Standard Time. Ask for GM Item Number 1825 when ordering.

SERVICE PROCEDURE

To correct this condition, dealers are to update the affected vehicles with the correct flash calibration program for the vehicle control module. The updated flash calibration for the affected vehicles will be included in the CD ROM shipped on May 31, 1996.

If it is necessary to correct this condition on units that are sold from your inventory prior to receiving the CD ROM call TechLine at 1-800-828-6860 to get a VCI (Vehicle Configure Index) Number. This VCI Number will give you access to the updated flash calibration. When calling TechLine have the VIN of the affected vehicle ready.

1. Transfer data from the Reprogrammable Control Module to the TECH 1.

2. Transfer files (connect Tech 1 to TechLine Terminal). Note: Be sure to use the updated flash calibration.

3. Transfer Files from the Tech 1 to the Reprogrammable Control Module.

4. Install Campaign Identification Label.

5. California dealers only, provide owner with a "Vehicle Emission Recall Proof Of Correction" certificate. Vehicles can be released for delivery when this service procedure is completed.

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 campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a 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 by the customer for periodic servicing. When installing the Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from 'VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering.

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

CLAIM INFORMATION

Submit a Product Campaign Claim with the information indicated below:

REPAIR PART FAILED PARTS LABOR LABOR NET PERFORMED COUNT PART NO. ALLOW CC-FC OP HOURS ITEM --------- ----- -------- ----- ----- ------ ----- -----

Reprogram VCM N/A N/A N/A MA-96 V9940 0.4 N/A

* For Campaign Administrative Allowance, add 0.1 hours to the "Labor Hours".

Refer to the General Motors Corporation Claims Processing Manual for details on Product Campaign Claim Submission.

Dear GMC/Chevrolet Customer:

This notice is sent to inform you that GMC/Chevrolet is conducting an emission recall campaign that includes your vehicle.

REASON FOR THIS RECALL

Certain 1996 Sonoma two-wheel drive Pickup Trucks equipped with 4.3L engine (LF6) and manual 5 speed transmission (M50), built at the Linden Assembly plant, may have an incorrectly programmed Vehicle Control Modules (VCM) for engine calibration. There are two possible programming errors. First, some vehicles intended for U.S. and export sale (engine calibration P/N 16232334) may have engine calibrations (P/N 16232335) intended for vehicles sold in Canada. Second, some of these two-wheel drive pickups intended for sale in Canada (P/N 16232335) may have engine calibrations (P/N 16232336) intended for four-wheel drive pickups sold in the U.S.

WHAT WE WILL DO

To correct this condition, your dealer will reprogram the vehicle VCM with the correct data files.

WHAT YOU SHOULD DO

Please contact your GMC/Chevrolet dealer as soon as possible to arrange a service date and to assure parts availability. Instructions for making this correction have been sent to your dealer. Please ask your dealer if you wish to know how much time will be needed to schedule, process and repair your vehicle.

The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Should your dealer not schedule a service date within a reasonable time, you should contact the GMC/Chevrolet Consumer Relations office. The telephone number of the Consumer Relations office is listed on your Warranty and Owner Assistance Information Manual.

To ensure your full protection under the emission warranty made available to your vehicle by state or Federal Law, and your right to participate in future recalls, it is recommended that you have your vehicle serviced as soon as possible. Failure to do so could legally be determined to be lack of proper maintenance of your vehicle. Also, your vehicle may fail a state or local emission inspection test if the recall work is not accomplished.

IMPORTANT MESSAGE FOR CALIFORNIA RESIDENTS

The California Air Resources Board (CARB) requires that vehicle emission recall campaigns be completed prior to California registration renewal. Uncorrected emission recall campaigns will result in the inability to renew your California vehicle registration.

At the time of emission campaign completion, your California dealer will issue a "Proof of Correction Certificate". Keep this certificate and, if required, present it to the Department of Motor Vehicles when renewing your California registration as proof of campaign completion.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our product.

Pontiac-GMC/Chevrolet Division GENERAL MOTORS CORPORATION

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.