Honda Civic Service Manual page 715

Description
Lock-up System (cont'dl
TOROUE CONVERTER
Half Lock-up
. Lock-up Control Solenoid Valve A: ON
Lock-up Control Solenoid Valve 8: Duty Operation
OFF - ON
Linear Solenoid Pressure: Low
The PCM switches the solenoid valve A on to release the
modulator pressure in the left cavity of the lock_up shift
valve. The modulator pressure in the right cavity of the
lock-up shift valve overcomes the spring force; thus the
lock-up shift valve is moved to the left side.
The line pressure is then separated into the two pas-
sages to the torque converter:
Torque Converter Inner pressure: enters into right
sade to engage lock-up clutch
Torque Converter Back pressure: enters into left side
to diseogage lock-up clutch
The back pressure (F2) is regulated by the lock-up con-
trol valve, whereas the position of the lock-up timing
valve is determined by the linear solenoid Dressure and
tension of the valve spring. Also the position of the lock_
up control valve is determined by the back pressure of
the lock-up control valve, torque converter pressure reg_
ulated by the torque converter check valve, and modula_
tor pressure determined by the lock-up control solenoid
valve B. The PCM switches the lock-up control solenoid
valve B on and off rapidly {duty operation} under certain
conditions to regulate the back pressure (F2) to lock the
torque convener properly.
NOTE: When used, "left" or "right" indicates direction
on the hvdraulic circuit.
MODULATOR PRESSURE
LINEAR SOLENOTD PRESSURE
LOCK.UP CONTROL
VALVE
LOCK.UP CONTROL
SOI.TNOID VALVE
A 8
TOROUE CONVERTER
CHECK VAI-VE
RELIEF VALVE
LOCK-UP TIMING
VALVE
^
L____J'r cooLER RELTEF
valvE
14-36
ATF PUMP