Page 439 of 1681
Description
Electronic Control System (cont'd)
Circuit Diagram and Terminal Locations
IGNITIONSWITCH
LOC(-UPCONTFOL
LOCK - UP COIITBOLSOLENOIO VALVE B
SHIFI CONTROLSOLENOID VALVE A
sHrFtc0NtRotSOLENOIDVALVES
€cT
SAFOS S
AT CHK
ACCt
scs
LG1
LG1
NMSG
NC
NCSG
vcc2
TPS
sG2
ECT
BAios s
AT CNI(
ACCt
LG1
LG2
257I10112356789lo
151620222324252612l417lg20
14-22
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Page 440 of 1681
The valve bodies include the main valve body, the secondary valve body, the regulator valve body, the servo body andthe lock-up valve bodv.
The ATF pump is driven by splines behind the torque converter which is attached to the engine, Fluid {lows through
the regulator valve to maintain specified pressure through the main valve body to the manual valve, directing pressure
to each of the clutches.
SHIFT CONTROL SOLENOIDVALVE ASSEMBLY
RIGHT SIDE COVER
LOCK'UP VALVE BODYSERVO BODY
SECONDARY VALVEBODY
VALVE BODY
REGULATOR VBODY
LOCK-UPOIL PUMP GEARS
SOLENOID VALVEASSEMBLYTOROUEHOUSING
{cont'd)
%<->--::/ )C)
IrY,
14_23
'
Page 441 of 1681
Description
Hydraulic Control (cont'd)
Regulator Valve Body
The regulator valve body is located on the main valve body. The regulator valve body consists of the regulator valve,
the torque converter check valve, the cooler check valve, and the lock-up control valve.
LOCK.UP CONTROL VALVE
Lock-up Valve Body
The lock-up valve body with the lock-up shift valve and lock-up timing B valve is located on the regulator valve body.
LOCK-UP SHIFY VALVE
TIMI[\'G B VALVE
REGUI-ATOR VALVE
COOLER CHECK VALVE
Page 445 of 1681

Description
Hydraulic Flow
G€n6.al Chart of Hydraulic Pr6sure
ATF Pump - Regulator Valve
Distribution of Hydraulic Pressuro
Line Pressure -----r- Modulator Pressure
F-- Thronle B PressureL Clutch Pressure
Toroue Convener Pressure
Lubrication Pressure
. Regulator Valve ----; Torque Converter Prossure
f- Lubricaiion PrassureL To Regulate Line Pressure
Manual Valve - To Select Line Pressure - Clutch Pressure
. Modulator Valve Modulator Pressure ---- --I----- Shift Control Solenoid ValvosL- Lock-uD Control Solenoid Valves
. 1-2 Shift Valve -----l
. 2-3 Shift Valve ----f- Clutch Pressure. 3-4 Shift Valve ----------r
. Throttle Valve - Throttle B Pressure
NO,DESCRIPTION OF PRESSURENO.DESCRIPTION OF PR€SSURENO.DESCRIPTION OF PRESSURE
1LINE6C
MODULATOR(LOCK.UP CONTROL
SOLENOID VALVE A)
55THROTTLE B
LINE6D
MODULATOR(LOCK-UP CONTROL
SOLENOID VALVE B)
56THROTTLE B
LINEaLINETHROTTLE B
LINE101ST CLUTCH5dTHROTTLE B
LINE151ST-HOLD CLUTCH90TOROUE CONVERTER
4LINElST.HOLD CLUTCH91TOROUE CONVERTER
LINE18LINE92TOROUE CONVERTER
5LINE202ND CLUTCH93ATF COOLER
LINE212ND CLUTCH94TOROUE CONVERTER
5'LINE25LINELUBRICATION
6MODULATOR303RD CLUTCH96TOROUE CONVERTER
MODULATOR313RD CLUTCH97TOBOUE CONVERTER
64MODULATOR(SHIN CONTROLSOLENOIO VALVE A)404TH CLUTCHooSUCTION
6BMODULATOR(SHIFT CONTROT SOLENOID VATVE B)414TH CLUTCHXBLEED
Page 455 of 1681
Description
Lock-up System
Lock-up Clutch
1. Operation (clutch on)
With the lock-up clutch on, the fluid in the chamber between the torque converter cover and lock-up piston is discharged,
and the converter fluid exerts pressure through the piston against the converter cover, As a result, the converter turbine islocked on the converter cover firmly. The effoct is to bypass the converter, thereby placing the vehicle in direct drive.
t-owerlrotl
The power flows by way of:
Engine
I
Drive plate
I
Torque converter
I
Lock-up piston
I
Damper spring
I
Turbine
I
Mainshatt
2. Operation (clutch otl)
With the lock-up clutch oft, the tluid flows in the reverse of "clutch on." As a result, the lock-up piston is moved away
from the converter cover; that is, the torque converter lock-up is released.
tro-wt rrotl
Engine
I
Drive plate
I
Torque converter cover
I
Pump
I
Turbine
Mainshaft
LOCK-UP PISTON
TOROUE CONVERTERCOVER
:1
14-38
TURBINE
tl
u
v
Page 456 of 1681

In E position in 2nd, 3rd and 4th, and E position in 3rd, pressurized fluid is drained from rhe back of the torque con-
verter 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 crankshatt. Together with hydraulic control, the TCM op-
timized the timing of the lock-up system. Under certain conditions, the lock-up clutch is applied during deceleration in
3rd and 4th gear.
The lock-up system controls the range of lock-up according to lock-up control solenoid valves A and B, and the throttle
valve B. 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 torque converter housing. and are controlled by the TCM.
LOCK,UP CONTROL
LOCT.UP SHIfT VALVE
AlF COOIER
tocK uP coNTno! valvE
Solenoid valve
L*r""r "o.Jtio" \B
Lock'up OFFOFFOFF
Lock-up, slightONOFF
Lock-up, halfONON
Lock-up, fullONON
LOCK-Updu.ing decelerationONDuty operationOFF - ON
IOCK UP TIMING B VATVE
(cont'd)
14-39
Page 457 of 1681
Description
LOC(,UP SlllFT VATVE
Lock-up System (cont'd)
No Lock-ug
The pressurized fluid regulated by the modulator works on both ends of the lock-up shift valve and on the left side ot
the lock-up control valve. Under this condition, the pressures working on both ends of the lock-up shift valve are equal.
the shift valve is moved to the right side by the tension of the valve spring alone. The tluid from the ATF pump will llow
through the left side of the lock-up clutch to the torque converter; that is, the lock-up clutch is in OFF condition.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
LOCX.UP CONTROI
LOCK.UP COITTFOT VATVE
MOOUTATOR PRESSURE
i
il
rl
I
IOCK IJP TIMING B VALVE
14-40
Page 458 of 1681

IPartial Lock-up
Lock-uo Control Solenoid Valve A: ONLock-uD Control Solenoid Valve B: OFF
The TCM switches solenoid valve A ON to release modulator Dressure 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, 8nd the lock-up shift valve is
moved to the left side,
Modulator pressure is separated into the two passages:
Torque Converter Inner Pressure: enters into right side to engage lock-up clutch,
Torque Converter Back Pressure: enters into left side to disengage lock-up clutch.
Back prassure {F2) is regulated by the lock-up control valve whereas the position of the lock-up timing B valve is deter-
mined by the throttle B pressure, tension of the valve spring, and pressure regulated by the modulator. Also the position
of the lock-up control valve is determined by the back prossure of the lock-up control valve and torque converter pressure
regulated by the check valve. With lock-up control solenoid valve B kept OFF. modulator pressure is maintained in the left
end of the lock-up control valve; in other words, the lock-up control valve is moved slightly to the left side. This slight
movement of the lock-up control valve causes the back pressure to be lowered slightly, resulting in partial lock-up.
NOTE: When used, "|eft" or "right" indicates direction on the hydraulic circuit.
LOCK.UP GO TNOLSOLENOIO VAIVE A
TOCK-UP SHIFT VAIVELOCI( UP COI{TROL VAIVE
T
LOC(,UP IM TG g VALV€
MODULATOB PNESSUFE
14-41