Page 555 of 1395

Lock-up System
TOROUE CONVERTER
In E position ('97 - 98 models) and in E position ('99 -
OO models) (3rd and 4th), and E position ('97 - 98 mod-
els) and in E position with Over-Drive (O/D) is OFF (by
pressing the O/D switch) ('99 - 00 models) (3rd), pressur-
ized fluid is drained from the back of the torque convert-
er through a fluid passage, causing the lock-up piston to
be held against the torque converter cover, As this takes
Dlace, the mainshaft rotates at the same speed as th8
engine crankshaft. Together with the hydraulic control,
the PCM optimizes the timing of the lock-up system.
Under certain condltions. the lock-up clutch is appli€d
during deceleration, in 3rd and 4th gear.
The lock-up system controls the range of lock-up sccord-
ing to lock-up control solenoid valves A and B, and ths
linear solenoid. When lock-up control solenoid valves A
and B activate. modulator pressure changes. Lock-up
control solenoid valves A and B are mounted on the out-
side of the torque converter housing, and the linear
solenoid is mounted on the transmission housing. They
are controlled bv the PCM.
The table below shows the lock-up conditions for lock-up
control solenoid valves and linear solenoid pressure.
LINEAR SOLENOID PRESSURE
(cont'd)
LOCK.UP CONTROL' VALVE
LOCK.UP CONTROLSOLENOID VALVE
AB
MODULATORPf,ESSURE
MAINSHAFT
COUNTERSHAFT
SUB.SHAFT
Lock-up
Conditions
Lock-up Conirol
Solenoid valveLinaal
Solenoid
PrgssulsAB
Lock-up OFFOFFOFFHigh
Lock-up, HalfONDuty operation
OFF - ONLow
Lock-up, FullONONHigh
Lock-up
during
deceleration
ONDuty operation
OFF - ON
RELIEF VALVE
LOCK'UP TIMINGVALVE
COOLER RELIEF VALVE
ATF COOLERATF STRAINER
ATF PUMP
14-39
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Page 556 of 1395
Description
Lock-up System (cont'dl
Lock-up Clutch
L Ooeration (clutch on)
With the lock-up clutch on, the fluid in the chamber between the torque convener cover and the lock-uD oiston is drainedoff, and the converter fluid exerts pressure through the piston against the torque converter cover, As a result, the conven-er turbine is locked to the converter cover. This bipasses the converter, placing the vehicle in direct drive.
LOCK,UP PISTON
The power flows by way of:
Engine
+
Drive plate
Torque converter cover
I
Lock-up piston
t
Damper spring
{
Turbine
Mainshaft
IOROUECOVER
Operation (clutch off)
With the lock-up clutch off, the fluid flows in the reverse of "clutch on." As a result, the lock-up piston moves away fromthe converter cover, and the torque converter lock-up is released.
Engine
I
Drive plate
{
Torque converter cover
{
Pump
I
Turbine
{
Mainshaft
TOROUECOVER
To ATF cooler{(1\\n1INLET
t
Jtl
ort
MAIf{SHAFT
MAII{SHAFT
14-40
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Page 557 of 1395
TOROUE CONVERTER
No Lock-up
. Lock-up Control Solenoid Valve A: OFF
. Lock-up Control Solenoid Valve B: OFF
. Linear Solenoid Pressure: High
The pressurized fluid regulated by the modulator works
on both ends of the lock-up shift valve. Under this condi-
tion, the pressures working on both ends of the lock-up
shift valve are equal. and the lock-up shift valve is
moved to the right side by the tension of the valve
spring. Fluid trom the ATF pump will flow through the
left side of the lock-up clutch to the torque converter; the
lock-up clutch is OFF.
NOTE: When us€d, "|eft" and "right" indicates direction
on the hydraulic circuit.
+ LINEAR SOLENOID PRESSURE
(cont'd)
LOCK.UP CONTROLSOI-ENOID VALVE
MOOULATORPRESSURE
MAINSHAFT
COUNTERSHAFTRELIEF VALVE
LOCK-UP TIMINGVALVE
i COOLER RELIEF VALVE
ATF STRAINERATF COOLER
ATF PUMP
14-41
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Page 558 of 1395

Description
Lock-up System (cont'dl
a
a
Half Lock-up
Lock-up Control Solenoid Valve A: ON
Lock-up Control Solenoid Valve B: Duty Operation
OFF - ON
Linear Solenoid Pressure: Low
The PCM switches solenoid valve A on to release modu-
lator pressure in the left cavity of the lock-up shift valve.
Modulator pressure in the right cavity of the lock-up
shift valve overcomes the spring force, and the lock-up
shift valve is moved to the left side.
Line pressure is then separated into the two passages to
the torque converter; torque converter inner pressure
enters into right side to engage the lock-up clutch, and
torque convener back Dressure enters into left side to
disengage the lock-up clutch.
Back pressure (F2) is regulated by the lock-up control
valve, whereas the position of the lock-up timing valve
is determined by linear solenoid pressure 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 (regulated by
the torque converter check valve), and modulator pres-
sure (determined by the lock-up control solenoid valve
B). The PCM switches lock-up control solenoid valve B
on and off rapidly (duty operation), under certajn condi-
tions, to regulate back pressur€ (F2) and lock the torque
convertef.
NOTE: When used, "left" and "right" indicates direction
on the hvdraulic circuit.
+ LINEAR SOLENOID PRESSURE
TOFOUE CONVERTER
L(rcK.UP CONTROLSOLENOID VALVE
AB
MODULATORPNESSURE
MAINSHAFT
COUNIERSHAFTRELIEF VALVE
L(rcK-UP TIMINGVALVE
COOLER RELIEF VALVE
ATF STRAINER
14-42
ATF COOLER
ATF PUMP
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Page 559 of 1395

TOROUE CONVEFTER
Full Lock-up
. Lock-up Control Solenoid Valve A: ON
. Lock-up Control Solenoid Valve B: ON
. Linear Solenoid Pressure: High
When the vehicle speed further increases, linear
solenoid pressure increases to high in accordance with
the linear solenoid which is controlled by the PCM.
The lock up timing valve overcomes the spring force
and moves to the left side. Also, this valve closes the
fluid port leading to the left side of the lock-up control
valve.
Under this condition, modulator pressure in the left side
of the lock-up control valve had already been released
by the lock-up control solenoid valve B; the lock-up con-
trol valve is moved to the left side. As this takes place,
torque converter back pressure is released fully, causing
the lock-up clutch to be engaged fully.
NOTE: When used. "left" and "right" indicates direction
on the hydraulic circuit.
+ LINEAR SOLENOIO PRESSURE
(cont'd)
LOCK-UP CONTROLSOLENOID VALVE
MODULATORPRESSURE
MAINSHAFT
COUNTERSHAFT
SUB-SHAFT
RELIEF VALVE
LOCK.UP TIMINGVALVE
COOLER BELIEF VALVE
ATF STRAINERATF COOLER
ATF PUMP
14-43
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Page 560 of 1395
Description
Lock-up System (cont'dl
a
a
Decelelation Lock-up
Lock-up Control Solenoid Valve A: ON
Lock-up Control Solenoid Valve B; Duty Operation
OFF - ON
Linear Solenoid Pressure: Low
The PCM switches solenoid valve B on and off rapidly
under certain conditions. The slight lock-up and half
lock-up regions are maintained to lock the torque con-
vener propeny.
NOTE: When used, "left" and "right" indicates direction
on the hydraulic circuit.
+ LINEAR SOLENOID PRESSURE
TOROUE CONVERTER
tMOOULATORPRESSURE
MAINSHAFT
COUNTERSHAFT
SUB.SHAFT
ATF COOLER
RELIEF VALVE
LOCK.UP TIMINGVALVE
COOLER RELIEF VALVE
14-44
ATF STBAINER
ATF PUMP
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Page 561 of 1395
Component Locations
ASSEMBLY
POWERTRAIN CONTROLMODULE {PCMI
COUNTERSHAFTSPEED SENSOR
AUTOMAIIC TRANSAXI.E(A/T} GEAR POSITIONswtTcH
\
CONTBOL UN]T
SHIFT CONTROLSOLEM)ID VALVEASSEMBLY
SPEED SCNSOR
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Page 565 of 1395

PCM CONNECTOR B (25P) lcont'd)
PCM CONNECTOR C {31PI
PCM CONNECTOR D II6PI
Terminal NumbelSignalDescriptionMeasuring Conditions/Terminal voltage
811SHBShift control solenoid valve B
control
In E, E position, in 1st and 2nd gear in -q,
Er position: Battery voltage
In B position, in 3rd gear in qd, q:l,in atn
gear in D. position: 0 V
812ILUlnterlock controlWhen ignition switch is ON (ll), brake pedal
deDressed and accelerator oedal released:0 V
B13D4 INDD4 Indicator light controlWhen ignition switch is first turned ON (ll): 6 V
or more for tlvo seconds
In lDll position: 6V or more
814NMSGMainshaft speed sensor ground
815NMMainshaft speed sensor signal
InpuI
Depending on engine speed: Pulsing signal
When engine is stopped: 0 V
816ATP RAy'T gear position switch Eposition signal input
In E position; OV
In other than E position: Battery voltage
817ATP 2Ay'T gear position switch E posi-
tion signal input
InEposition:0V
In other than E position: Battery voltage
B18ATP 1A/T gear position switch El posi-
tion signal input
InEposition:0V
In other than E position: Battery voltage
819 to 821Not used
B 22NCSGCountershaft speed sensor ground
NCCountershaft speed sensor signal
Inpur
Depending on vehicle speed: Pulsing signal
when vehicle is stooped: 0 V
824ATP D4A/T gear position switch iql posi-
tion signal input
In E position: 0V
In other than lgal position: Baftery voltage
825ATP NPAy'T gear position switch E and
N position signals input
In E and E positions: 0V
In otherthan @ and ffi positions:5 V
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Voltage
SCSService check signalWith ignition switch ON (ll) and service check
connector open: 5 V
With ignition switch ON (ll) and service check
connector connected with special tool: 0 V
c10VBUBack-up power system(under-hood Fuse 47)
Always battery voltage
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Voltage
STOP SWBrake switch signal inputBrake pedal pressedr Battery voltage
Brake pedal released: 0 V
14-49
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