CAMPAIGN: OMISSION OF LOW OIL PRESSURE WARNING OF THE ENG.

SUBJECT: OMISSION OF LOW OIL PRESSURE WARNING ON THE ENGINE ALARM/SHUTDOWN FEATURE

MODELS: 1995 GMC C6/7 Medium Duty Trucks Equipped with Diesel Engines (RPO LXO) and Engine Alarm/Shutdown Feature (RPO KPJ)

TO: ALL GENERAL MOTORS DEALERS

General Motors of Canada Limited has determined that on CERTAIN 1995 GMC C6/7 Medium Duty Trucks equipped with diesel engines (RPO LXO) and the automatic engine shutdown option (KPJ) and built before March 24, 1995, the "Low Oil Pressure" feature was not provided in the released design. Without this feature (which the customer paid for) if a "low oil pressure" condition occurred, the driver would not receive the expected warning and severe engine damage could occur.

To correct this condition, dealers will replace the existing circuit board in the shutdown module with one containing a jumper to pin A7.

VEHICLES INVOLVED:

Involved are CERTAIN 1995 GMC C6/7 Medium Duty Trucks equipped with diesel engines (RPO LXO) and engine alarm and shutdown feature (RPO KPJ) built within the following VIN breakpoints:

Year Model Plant Plant Code From Through

1995 GMC Janesville J SJ500014 SJ519883

NOTE: PLEASE CHECK DCS SCREEN 45 OR YOUR V.I.N. LISTING BEFORE PERFORMING CAMPAIGN TO ENSURE THAT THE VEHICLE IS AFFECTED. ONLY AFFECTED VIN'S 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 NUST 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 kilometers 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 die 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 Campaigns. 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 campaign activity only and should not be used for any other purpose.

PARTS INFORMATION:

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

Part Number Description Quantity/Vehicle ----------------------------------------------------------------------------- 15727949 Engine Alarm and Shutdown Module (LXO & KPJ & JE4) 1 15727950 Engine Alarm and Shutdown Module (LXO & KPJ & JE3) 1

PARTS AND LABOR 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 R & R Engine Alarm/Shutdown Module .5

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:

NOTICE: Many solid state electrical components can be damaged by Electrostatic Discharge (SD). Some will display a symbol but many will not. Be sure to follow the ESD Sensitive procedures listed in the 1995 TopKick Service Manual, Section 8C - "Handling Electrostatic Discharge Sensitive Parts" when performing the following procedure. Failure to do so could result in damage to the instrument cluster components.

1. Disconnect the negative battery cable.

2. Remove the floor vent duct.

3. Locate the engine alarm/shutdown module. The module is in a black plastic case.

- The module is located on the LH side of the vehicle, above the kick panel on the vertical sheet metal, near the floor vent duct and behind the Instrument Panel (I/P).

4. Unsnap the inboard side of the module case cover. The cover has four snaps, two on each side.

IMPORTANT: Only unsnap the inboard side of the case. It is not necessary to remove the cover from the module assembly.

- Unsnap the inboard side of the case only. This is a blind operation. The case has a left-hand hinge and opens right to left.

5. Remove the circuit board from the module case.

- Gently wiggle the circuit board to remove it from the case. This is a blind operation.

6. Disconnect the wiring harness from the circuit board. Squeeze the blue main connector to remove.

7. Disconnect the four prong pigtail from the main harness connector.

8. Reconnect the wiring harness into the circuit board.

9. Install the new circuit board in the module case. Position the four prong pigtail in the module case access slot and close the cover.

IMPORTANT: If the module case cover was removed for any reason, the cover must be installed with the hole for the speaker located toward the top of the module.

10. Reconnect the four prong pigtail into the main harness connector.

11. Reconnect the wiring harness into the circuit board.

12. Reinstall the left floor vent duct.

13. Reconnect the negative battery cable.

14. Install "Campaign Identification Label."

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.

As a valued customer, your complete satisfaction with your GMC truck is our goal. In keeping with this goal, we want to let you know that we have discovered a problem that could affect your vehicle and we want to take care of it at no charge to you.

On CERTAIN 1995 GMC C6/7 Medium Duty Trucks equipped with diesel engines and the automatic engine shutdown option and built before March 24, 1995, the "Low Oil Pressure" feature was not provided in the released design. Without this feature, if a "low oil pressure" condition occurred, the driver would not receive the expected warning and severe engine damage could occur.

To be absolutely sure that your vehicle is to specifications, your dealer will replace the existing circuit board in the shutdown module with one containing a jumper to pin A7.

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 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.