A/T - High Idle/Intermittent Code 26, Improper TPS

Bulletin No. T 85-7
File In Group 6C
Number 85
Date Sept. '84
SUBJECT: HIGH IDLE AND/OR INTERMITTENT CODE 26

MODELS AFFECTED: ALL 1981-1985 MODELS EQUIPPED WITH DFI

THROTTLE POSITION SENSOR TYPES:

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 areas 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