CAMPAIGN: CATALYTIC CONVERTER WELDED INTO EXHAUST PIPE. GMC Truck GMC C Pickup

SUBJECT: CATALYTIC CONVERTER WELDED INTO EXHAUST PIPE BACKWARDS ---------------------------------------------

MODELS: 1996 C/K TRUCKS WITH HEAVY DUTY EXHAUST EMISSIONS --------------------------------------------------

General Motors has decided that some 1996 C/K pickups and chassis-cabs with 5.7L (L31) or 7.4L (L29) gasoline engines and heavy duty exhaust emissions may have been built with catalytic converters that were welded into the exhaust pipe backwards. In this configuration, the engine may not meet the configuration specified in the emissions Application for Certification.

To correct this condition, dealers will inspect to see if the catalytic converter is installed in the proper orientation. If not, the exhaust crossover pipe assembly will be replaced.

Involved are CERTAIN 1996 C/K pickups and chassis-cabs with 5.7L (L31) or 7.4L (L29) gasoline engines and heavy duty exhaust emissions built within the following VIN breakpoints:

Plant Year Model Code From Through ---- ----- ----- ------ ------- 1996 C/K F TF000003 TF003254 1996 C/K E TE502575 TE506508 1996 C/K Z TZ500446 TZ502826

The specific vehicles involved in this campaign have been identified by Vehicle Identification Number (VIN) Computer Listings. These listings are furnished to all involved dealers with the campaign bulletin. Dealers should confirm vehicle eligibility through VISS (Vehicle Information Service System) or SERVICENET prior to beginning campaign repairs.

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 owners take possession of these vehicles.

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 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 the name and address of the owner of an involved vehicle was unavailable to GMC 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.

Pontiac-GMC Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170

When an emissions campaign is completed, California retailers must provide the vehicle owner a "Campaign Certificate of Completion" which the owner may present to the Califomia Department of Motor Vehicles (DMV) when renewing their vehicle registration. Without this certificate, the owner may be unable to renew their vehicle registration, causing owner dissatisfaction. Additional "Campaign Certificates of Completion" 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 GM Item Number 1825 when ordering.

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by GMC 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

Inspection And Repair Procedure For "C" Model (2 Wheel Drive):

1. Raise vehicle.

2. Inspect configuration of driver's side forward catalytic converter (Figure 1, Item 1). Stamped "AC" logo on converter must be located on the downstream end of converter (i.e. towards the rear of the vehicle). * If converter is configured properly, proceed to step #19. * If converter is installed backwards, proceed to step #3.

3. Remove left side oxygen sensor, including electrical connector (Figure 1, Item 2).

4. Remove right side oxygen sensor, including electrical connector (Figure 1, Item 3).

5. Support transmission with trans jack.

6. Remove transmission crossmember bolts, trans mount nut, and reposition crossmember rearward.

7. Remove bolts from catalytic converter to exhaust pipe flange (Figure 1, Item 4).

8. Remove left crossover pipe at manifold (Figure 1, Item 5).

9. Remove right crossover pipe at manifold (Figure 1, Item 6).

10. Remove crossover pipe/converter assembly (Figure 1).

11. Install new crossover pipe/converter assembly in position on vehicle (Figure 1).

12. Install right crossover pipe at manifold and torque nuts to 65 Nm (48 lb. ft.) Figure 1, Item 6).

13. Install left crossover pipe at manifold and torque nuts to 65 Nm (48 lb. ft.) Figure 1, Item 5).

14. Re-install bolts in catalytic converter to exhaust pipe flange and torque to 48 Nm (35 lb ft.) Figure 1, Item 4).

15. Reposition and reinstall transmission crossmember and torque bolts 77 N, (57 lb. ft.) and trans mount nut torque nut to 52 Nm (38 lb ft).

16. Remove transmission jack

17. Re-install right side oxygen sensor, including electrical connector, (Figure 1, Item 3) and torque to 41 Nm (30 lb ft.)

18. Re-install left side oxygen sensor, including electrical connector, (Figure 1, Item 2) and torque to 41 Nm (30 Lb. ft.)

19. Lower vehicle

20. Install Campaign Identificastion Label

Inspection and Repair Procedure for "K" Model (4 Wheel Drive):

1. Raise Vehicle

2. Inspect configuration of drivers side forward catalytic converter (Figure 1, Item 1). Stamped "AC" logo on converter must be located on the downstream end of the converter (i.e. towards the rear of the vehicle.) * If converter is configured properly, proceed to step #17. * If converter is installed backwards, proceed to step #3.

3. Remove left side oxygen sensor, including electrical connector (Figure 1, Item 3).

4. Remove right side oxygen sensor, including electrical connector (Figure 1, Item 3).

5. Remove transmission pan shield.

6. Remove bolts from catalytic converter to exhaust pipe flange (Figure 1, Item 4).

7. Remove left crossover pipe at manifold (Figure 1, Item 5).

8. Remove right crossover pipe at manifold (Figure 1, Item 6).

9. Remove crossover pipe/converter assembly (Figure 1).

10. Install new crossover pipe/converter assembly in position on vehicle (Figure 1).

11. Install right crossover pipe at manifold and torque nuts to 65 Nm (48 lb. ft. (Figure 1, Item 6)

12. Install left crossover pipe at manifold and torque nuts to 65 Mn (48 lb ft.) (Figure 1, Item 5).

13. Re-install bolts in catalytic converter to exhaust pipe flange and torque to 48 Nm (35 lb. ft.) (Figure 1, Item 4).

14. Re-install transmission pan shield.

15. Re-install fight side oxygen sensor, including electrical connector (Figure 1, Item 3) and torque to 41 Nm (30 lb. ft.)

16. Re-install left side oxygen sensor, including electrical connector (Figure 1, Item 2), and torque to 41 Nm (30 lb. ft.).

17. Lower vehicle

18. Install Campaign Identification Label

PARTS INFORMATION

Parts required to complete this campaign are to be obtained from General Motors Service Parts Operations (GMSPO). Please refer to your "involved vehicle listing" prior to ordering requirements. Normal orders should be placed on a DRO = Daily Replenishment Order. An emergency requirement should be ordered on a CSO = Customer Special Order.

Part Number Description Model Quantity ----------- ----------- ----- -------- 15733227 Exhaust Crossover With Converter K2, 3 1 With L29, MW3

15733228 Exhaust Crossover With Converter K2, 3 1 With L31, MW3

15733230 Exhaust Crossover With Converter C2,3 1 With L29 & MT1 or MW3 K2, 3 With L29 & MT1

15733231 Exhaust Crossover With Converter C2, 3 1 With L31 & MT1 or MW3 K2,3 With L31 & MT1

WARRANTY INFORMATION

Dealers should submit a warranty claim on each vehicle completed under this campaign.

Part Parts CC-FC Labor *Labor Description Count Allow Op Hrs ------------ ----- ----- ----- ------ -------

C/K Truck- ---- ---- MA-96 V9910 0.3 Crossover Pipe/ Converter Inspect Only

C Truck- 1 MA-96 V9911 1.0 Crossover Pipe/Converter Inspect & Replace

K Truck- 1 MA-96 V9912 0.8 Crossover Pipe/Converter Inspect & Replace

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

** The "Parts Allowance" should be the sum total of the current GMSPO Dealer Net price plus 40% of all parts required for the repair.

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 five (5) digit dealer code of the dealer performing the campaign service. This information must be inserted with a typewriter or ball point pen. This label is to be used in conjunction with the clear protective plastic cover provided with the Campaign Identification Labels.

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.

Additional Campaign Identification Labels and covers are available in sheets of 49 by calling VISPAC, Incorporated at 1-800-269-5100 (Monday through Friday 8:00 AM to 4:30 PM EST).

ADMINISTRATIVE PROCEDURE

Procedures covering this campaign are outlined in Section IV of your dealership's "WINS Claims Processing Manual".

Dear GMC Customer:

To correct this condition, your GMC dealer will inspect to see if the catalytic converter is installed in the proper orientation. If not, the exhaust crossover pipe assembly will be replaced. Instructions for performing this service have been sent to your GMC dealer, and parts are available. Please contact your GMC dealer to arrange a service date as soon as possible. This procedure will take approximately 20 to 50 minutes to complete, but you should ask how much additional time your dealer will need to schedule and process your vehicle.

Your GMC dealer is best equipped to provide service to ensure your vehicle is corrected as promptly as possible. However, if you take your vehicle to your dealer on the agreed service date and they do not service this condition on that date or within five days, we recommend you contact GMC Consumer Relations. Consumer Relations will assist you and your dealer in getting your vehicle corrected. The telephone number of the Consumer Relations office is listed in your Warranty and Owner Assistance Information Manual.

To ensure your full protection under the emission warranty made applicable to your vehicle by 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. Should your dealer find that your emission system has been intentionally disabled, you will be asked if you wish the system to be restored so that it will function as designed. The cost of such restoration will be your responsibility.

The enclosed postage paid owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction to your vehicle in the shortest possible time. If you have sold or traded your vehicle, please furnish us the complete name and address of the person you sold or traded your vehicle to and return the card to us.

IMPORTANT MESSAGE FOR CALIFORNIA RESIDENTS

The California Air Resources (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 "Campaign Certificate of Completion". 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 DIVISION General Motors Corporation

96C21 Enclosure

Object Number: 79808 Size: FS

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.