CAMPAIGN:BRAKE BOOSTER VACUUM HOSE DETACHMENT. GMC Truck S15 Pickup

SUBJECT: BRAKE BOOSTER VACUUM HOSE DETACHMENT

MODELS: 1994 Chev SIO/GMC Sonoma Pickups With 2.2L Engine (RPO LN2)

TO ALL GENERAL MOTORS DEALERS

General Motors of Canada Limited has determined that a defect, which relates to motor vehicle safety, exists in certain 1994 Chev/GMC S Pickups with 2.2L engines (LN2). The vehicles may have the vacuum hose detached from the brake booster check valve as a result of engine backfire. This would result in increased engine idle and loss of brake power assist after depletion of the booster vacuum reserve; however, manual braking with increased pedal pressures would still be available. This detachment could occur with no warning to the driver and, if the booster vacuum reserve were depleted, the significant increase in brake pedal pressure experienced by the driver combined with the increased engine rpm when minimal stopping distances were required could result in a vehicle crash.

To correct this condition, dealers will install a clamp on the power brake booster hose at the brake booster check valve end.

VEHICLES INVOLVED:

Involved are certain 1994 Chev/GMC S Pickups with 2.2L engines built within the following VIN breakpoints:

Year Model Plant Plant Code From Through

1994 Chev Linden K SOP RK130608 1994 Chev Shreveport 8 SOP R8146473 1994 GMC Linden K SOP RK509121 1994 GMC Shreveport 8 SOP R8510713

NOTE: PLEASE CHECK DCS SCREEN 45 OR YOUR V.I.N. LISTING BEFORE PERFORMING CAMPAIGN TO ENSURE THAT THE VEHICLE IS AFFECTED. ONLY AFFECTED VINS WILL BE PAID.

All affected vehicles have been identified by the VIN listing provided to involved dealers with this bulletin. Any dealer not receiving a listing was not shipped any of the affected vehicles.

DEALER CAMPAIGN RESPONSIBILITY:

All unsold new vehicles in dealer's possession and subject to this campaign must be held and inspected/repaired per the Service Procedure of this Campaign Bulletin before owners take possession of these vehicles.

Dealers are to perform this campaign on all involved vehicles at no charge to owners, regardless of kilometres traveled, age of vehicle, or ownership, from this time forward.

Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to instructions contained in this bulletin. This could be done by mailing to such owners a copy of the owner letter accompanying this bulletin. Campaign follow up cards should not be used for this purpose, since the owner may not as yet have received the notification letter.

In summary, whenever a vehicle subject to this campaign is taken into your new or used 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.

CAMPAIGN PROCEDURE:

Refer to Section 4 of the Service Policies and Procedures Manual for the detailed procedure on handling Product Campaips. Dealers are requested to complete the campaign on all transfers as soon as possible.

OWNER NOTIFICATION:

All owners of record at the time of campaign release are shown on the attached computer listing and have been notified by first class mail from General Motors (see copy of owner letter included with this bulletin). The listings provided are for campaip activity only and should not be used for any other purpose.

PARTS INFORMATION:

Parts required to complete diis campaign should be ordered through regular channels, as follows:

Part Number Description Ouantity/Vehicle

12337891 Clamp 1

PARTS AND LABOUR CLAIM INFORMATION:

Credit for the campaign work performed will be paid upon receipt of a properly completed campaign claim card or DCS transmission in accordance with the following:

Repair Code Description Time Allowance

2A Install Clamp, Power Brake Booster Hose .3

Time allowance includes 0.1 hour for dealer administrative detail associated with this campaign. Parts credit will be based on dealer net plus 40% to cover parts handling.

SERVICE PROCEDURE:

1. Remove the power brake booster hose from the power brake booster check valve.

2. Install clamp (P/N 12337891) on hose.

3. Reinstall the power brake booster hose on the power brake booster check valve.

4. Secure clamp.

5. Install campaign identification label as defined below.

INSTALLATION OF CAMPAIGN IDENTIFICATION LABEL:

Clean surface of radiator upper mounting panel and apply a Campaign Identification Label. Make sure the correct campaign number is inserted on the label. This will indicate that the campaign has been completed.

Dear General Motors Customer:

General Motors of Canada Limited has determined that a defect, which relates to motor vehicle safety, exists in certain 1994 Chev SIO/GMC Sonoma Pickups with 2.2L engines (LN2). The vehicles may have the vacuum hose detached from the brake booster check valve as a result of engine backfire. This would result in increased engine idle and loss of brake power assist after depletion of the booster vacuum reserve; however, manual braking with increased pedal pressures would still be available. This detachment could occur with no warning to the driver and, if the booster vacuum reserve were depleted, the significant increase in brake pedal pressure experienced by the driver combined with the increased engine rpm when minimal stopping distances were required could result in a vehicle crash.

To correct this condition, your dealer will install a clamp on the power brake booster hose.

This service will be provided for you at no charge.

Please contact your GM dealer as soon as possible to arrange a service date.

If parts are required, ask your dealer for details regarding their availability. If parts are not in stock, they can be ordered before scheduling your service date.

This letter identifies your vehicle. Presentation of this letter to your dealer will assist their Service personnel in completing the necessary correction to your vehicle in the shortest possible time.

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

Customer Support Department General Motors of Canada Limited

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.