Regal V6-173 2.8L (1988)
Torque Converter Clutch: Technical Service Bulletins
Engine Controls - Revised Chart C-8A & C-8C, TCC
Bulletin 89-6
Date Mar., '89
Ref. No. 89-087-6E
Corp. Ref. No. 916503
SUBJECT:
SERVICE MANUAL UPDATE-SECTION 6E-DRIVEABILITY AND EMISSIONS-REVISED CHARTS C-8A, C-8C
MODELS AFFECTED:
1988 & 1989 REGAL WITH 2.8L (VIN CODE W) OR 3.1L (VIN CODE T)
This bulletin revises the Facing Page and Chart for C-8A (Page 1 of 2) and C-8C (Page 1 of 3) Torque Converter Clutch (TCC) Electrical Diagnosis in
Section 6E "Driveability And Emissions" of the 1988-89 Service Manual for the "W" Carline with 2.8L LB6 (VIN W) and 3.1L LHO (VIN T) V6
engines. Terminal "F" of the ALDL for TCC has been deleted. The revised diagnostic procedure is attached.
CHART C-8A
(Page 1 of 2)
440-T4 TORQUE CONVERTER CLUTCH (TCC) (ELECTRICAL DIAGNOSIS)
Circuit Description:
2.8L (VIN W) "W" CARLINE (PORT) The purpose of the automatic transmission torque converter clutch
feature is to eliminate the power loss of the torque converter stage when the vehicle is in a cruise condition.
This allows the convenience of the automatic transmission and the fuel economy of a manual transmission.
The heart of the system is a solenoid located inside the automatic transmission which is controlled by the
ECM. When the solenoid coil is activated ("ON"), the torque converter clutch is applied which results in
straight through mechanical coupling from the engine to transmission. When the transmission solenoid is
deactivated, the torque converter clutch is released which allows the torque converter to operate in the
conventional manner (fluidic coupling between engine and transmission). The TCC will engage on a warm
engine under given road load in 3rd and 4th gears. TCC will engage when:
^
Engine warmed up
^
Vehicle speed above a calibrated value (about 28 mph 45 km/h)
^
Throttle position sensor output not changing, indicating a steady road speed
^
Brake switch closed