Honda Civic 1998 Service Manual page 473

TOROUE CONVERTER
In igd position, in 3rd and 4th, and D3- position in 3rd,
pressurized fluid is drained from the back of the torque
converter through a fluid passage, causing the lock-up
piston to be held against the torque converter cover. As
this takes place, the mainshaft rotates at the same speed
as the engine crankshaft. Together with the hydraulic
c o n t r o l , t h e P C M o p t i m i z e d t h e t i m i n g o f t h e l o c k - u p
system. Under certain conditions, the lock-up clutch is
applied during deceleration, in 3rd and 4th gear.
The lock-up system controls the range ot lock-up accord-
ing to lock-up control solenoid valves A and B, and the
linear solenoid. When lock-up control solenoid valves A
and B activate. modulator pressure changes. Lock-up
control solenoid valves A and B and the linear solenoid
a r e m o u n t e d o n t h e o u t s i d e o f t h e t o r q u e c o n v e r t e r
housing, and are controlled by the PCM.
Lock-up Conditions/Lock-up Control Solenoid Valves/
Linear Solenoid Pressure
MODULATOR PRESSURE
<-
LINEAR SOLENOID PRESSURE
(cont'dl
Lock-up
Conditions
Lock-up Control
Solenoid Valve
Linear
Solenoid
Pressure
A
B
Lock-up OFF O F F
OFF
H i g h
Lock-up, Half O N
Duty operation
OFF - ON
Lock-up, Full O N O N H igh
LOCX-Up
during
deceleration
ON
Duty operation
OFF - ON
IOROUE CONVERTER
CHECK VALVE
RELIEF VAL
LOCK.UP TIMING
VALVE
",
.X, COOLER RELIEF VALVE
ATF PUMP
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