HIGH IDLE/INTERMITTENT CODE 26 INCORRECT TPS SENSOR

MODELS AFFECTED: ALL 1981-1985 MODELS EQUIPPED WITH DFI

Some 1981-1985 DFI equipped vehicles may experience a high idle and/or an intermittent code 26, under various operating conditions due to the installation of an improper Throttle Position Sensor (TPS) while servicing the vehicle.

The 1981 V8-6-4 TPS, although similar in appearance, is different electrically than the ones used for 1982-1984 HT4100 equipped vehicles. The ECM will not interpret the throttle angle correctly if these parts are interchanged. A 1981 V8-6-4 TPS installed on an HT4100 equipped vehicle can be diagnosed by a higher than normal throttle angle at warm idle (i.e., 4-6 degrees on parameter .0.1 vs. approximately 0-2 degrees on a normal vehicle) when the TPS is properly adjusted. The 1984 TPS is different in appearance than the 1981-1983 TPS.

As with all electrical and emissions-related parts, it is essential that the correct service part be used. Part numbers are as follows:

Model Year Engine Service P/N TPS "I.D." Application ---------- ------ ----------- ---------- ----------- Type 1 1981-1984 368 CID (V8-6-4) 17067979 59085 "D" Limousine and 1981 C, E, K Type 2 1982-1983 HT4100 17078259 70898 C/E/K Type 3 1984-1985 HT4100 17110352 74958 DW/DM/E/K (Excluding Limousine)

TPS "I.D." LOCATIONS

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.