K 1500 Truck 4WD V6-262 4.3L (1991)
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Technical Service Bulletin # 91C50
Date: 950201
Recall - Oxygen Sensor Replacement
No.: 90-C-50
Group: 6F Engine Exhaust
February, 1995
SUBJECT:
OXYGEN SENSOR REPLACEMENT (CALIFORNIA VEHICLES ONLY)
MODELS:
1991 C/K TRUCKS, M/L AND G VANS WITH 4.3L ENGINES AND CALIFORNIA EMISSIONS RPO NB2
General Motors has determined that CERTAIN 1991 C/K Trucks, M/L and G Vans with 4.3L engines (RPO LB4 - VIN Code "Z") and M Vans
equipped with 4.3L (RPO LU2 VIN Code "B") may be emitting non-methane hydrocarbons (NMHC) in excess of California emission standards.
California emission standards were established to protect the public health and welfare from dangers of air pollution. Excess emission of NMHC may
cause a vehicle to fail state mandated emission tests.
To correct this condition, dealers are to install a new exhaust oxygen sensor.
Vehicles Involved
VEHICLES INVOLVED
Involved are CERTAIN 1991 C/K Trucks, M/L and G Vans equipped with 4.3L engines sold in California:
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 and Administrative Information
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.
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 Truck 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.
GMC Truck Division
General Motors Corporation
101 Union Street
Plymouth, Michigan 48170