CCC TPS DIAGNOSIS WILL NOT SET CODE 21

1981 C-CARS EQUIPPED WITH 4.1 LITER V-6 CCC ENGINE WILL NOT SET A MALFUNCTION CODE 21 OR ILLUMINATE THE CHECK ENGINE LIGHT FOR A TPS FAULT. SHOULD THE TPS SIGNAL BE OPEN, THE VEHICLE WILL EXHIBIT A RICH CONDITION, POOR IDLE QUALITY, AND POOR FUEL ECONOMY. IN ADDITION, THE TORQUE CONVERTER CLUTCH WILL NOT ENGAGE. TO DIAGNOSE THIS CONDITION, USE THE SYSTEM PERFORMANCE CHECK DIAGNOSTIC CHART (PAGE 8D-137 IN 1981 SERVICE INFORMATION MANUAL). IF THE TPS CIRCUIT IS OPEN, IT WILL RESULT IN A FIXED DWELL UNDER 10 DEGREES, AND LEAD TO CHART #1. THE REVISED CHART #1 (SEE BELOW) WILL LEAD TO CHART 21 IF A TPS FAULT EXISTS. * SEE BULLETIN *

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.