TOYOTA SUPRA 1995 Service Repair Manual

± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATIONAT1±5

HYDRAULIC CONTROL SYSTEM
The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves and the
clutches and brakes, as well as the fluid passages which connect all of these components. Based on the
hydraulic pressure created by the oil pump, the hydraulic control system governs the hydraulic pressure
acting on the torque converter clutch, clutches and brakes in accordance with the vehicle driving condi-
tions.
There are three solenoid valves on the valve body. These solenoid valves are turned on and off by signals
from the ECM to operate the shift valves. These shift valves then switch the fluid passages so that fluid
goes to the torque converter clutch and planetary gear units.
Except for the solenoid valves, the hydraulic control system of the electronically controlled transmission
is basically the same as that of the fully hydraulic controlled automatic transmission.
HYDRAULIC CONTROL SYSTEM
VALVE BODY
OIL PUMP
ECMSOLENOID VALVES
CLUTCHES & BRAKES
Hydr. pressure control
Fluid passage switchingPlanetary gear sets
Torque Converter Clutch
w LINE PRESSURE
Line pressure is the most basic and important pressure used in the automatic transmission, because it is
used to operate all of the clutches and brakes in the transmission.
If the primary regulator valve does not operate correctly, line pressure will be either too high or too low. Line
pressure that is too high will lead to shifting shock and consequent engine power loss due to the greater
output required from the oil pump; line pressure that is too low will cause slippage of clutches and brakes,
which will, in extreme cases, prevent the vehicle from moving. Therefore, if either of these problems are
noted, the line pressure should be measured to see if it is within standard.
w THROTTLE PRESSURE
Throttle pressure is always kept in accordance with the opening angle of the engine throttle valve. This
throttle pressure acts on the primary regulator valve and, accordingly, line pressure is regulated in re-
sponse to the throttle valve opening.
In the fully hydraulic controlled automatic transmission, throttle pressure is used for regulating line pressure
and as signal pressure for up±shift and down±shift of the transmission. In the electronically controlled
transmission, however, throttle pressure is used only for regulating line pressure. Consequently, improper
adjustment of the transmission throttle cable may result in a line pressure that is too high or too low. This,
in turn, will lead to shifting shock or clutch and brake slippage. AT1±6
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATION

ELECTRONIC CONTROL SYSTEM
The electronic control system, which controls the shift points and the operation of the lock±up clutch, is
composed of the following three parts:
1. Sensors
These sensors sense the vehicle speed, throttle opening and other conditions and send this data to the
ECM in the form of electrical signals.
2. ECM
The ECM determines the shift and lock±up timing based upon the signals from sensors, and controls the
solenoid valves of the hydraulic control unit accordingly.
3. Actuators
These are three solenoid valves that control hydraulic pressure acting on the hydraulic valves to control
shifting and lock±up timing.
SENSORSECM
DRIVING PATTERN
SELECTOR
PARK/NEUTRAL
POSITIOIN SWITCH
THROTTLE POSITIOIN
SENSOR
VEHICLE SPEED
SENSOR
STOP LIGHT SWITCH
O/D MAIN SWITCH
CRUISE CONTROL
ECU
ENGINE COOLANT TEM-
PERATURE SENSOR
A/T FLUID
TEMPERATURE SENSOR
Back±up system
Self±diagnostic
system
Control of lock±
up timing
Control of shift
timing
ACTUATORS
NO. 1
SOLENOID VALVE
NO. 2
SOLENOID VALVE
LOCK±UP
SOLENOID VALVE
O/D OFF INDICA-
TOR LIGHT
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATIONAT1±7

FUNCTION OF ECU
w Control of Shifting Timing
The ECM has programmed into its memory the optimum shift pattern for each shift lever position (D, 2, L
position) and driving mode (Normal or Manual).
Based on the appropriate shift pattern, the ECM turns No.1 and No.2 solenoid valves on or off in accor-
dance with the vehicle speed signal from the vehicle speed sensor and the throttle opening signal from the
throttle position sensor. In this manner, the ECM operates each shift valve, opening or closing the fluid pas-
sages to the clutches and brakes to permit up±shift or down±shift of the transmission.
HINT: The electronic control system provides shift timing and lock±up control only while the vehicle is travel-
ing forward. In REVERSE, PARK, and NEUTRAL, the transmission is mechanically, not electronically con-
trolled.
w Control of Overdrive
Driving in overdrive is possible if the O/D main switch is on and the shift lever is in the D position. However,
when the vehicle is being driven using the cruise control system (CCS), if the actual vehicle speed drops
to about 4 km/h (2 mph) below the set speed while the vehicle is running in overdrive, the CCS ECU sends
a signal to the ECM to release the overdrive and prevent the transmission from shifting back into overdrive
until the actual vehicle speed reaches the speed set in the CCS memory.
On this model, if the engine coolant temperature falls below 60°C (140°F), the ECM sends a signal to the
ECM, preventing the transmission from up±shifting into overdrive.
w Control of Lock±Up System
The ECM has programmed in its memory a lock±up clutch operation pattern for each driving mode (Normal
of Manual). Based on this lock±up pattern, the ECM turns lock±up solenoid valve on or off in accordance
with the vehicle speed signals received from the vehicle speed sensor and the throttle opening signals from
the throttle position sensor.
Depending on whether lock±up solenoid valve is on or off, the lock±up relay valve performs changeover
of the fluid passages for the converter pressure acting on the torque converter clutch to engage or disen-
gage the lock±up clutch.
Mandatory Cancellation of Lock±Up System:
If any of the following conditions exist, the ECM turns off lock±up solenoid valve to disengage the lock±up
clutch.
1) The brake light switch comes on (during braking).
2) The IDL points of the throttle position sensor close (throttle valve fully closed).
3) The vehicle speed drops 4 km/h (2 mph) or more below the set speed while the cruise control system
is operating.
4) The engine coolant temperature falls below 60°C (140°F) and vehicle speed is under 60 km/h (37
mph), or 35°C (95°F) and vehicle speed is under 40 km/h (25 mph).
The purpose of 1) and 2) above is to prevent the engine from stalling if the rear wheels lock up.
The purpose of 3) is to cause the torque converter clutch to operate to obtain torque multiplication. The
purpose of 4) is both to improve general driveability, and to speed up transmission warm±up.
Also, while the lock±up system is in operation, the ECM will temporarily turn it off during up±shift or down±
shift in order to decrease shifting shock. AT1±8
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATION

SYSTEM DIAGRAM
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATIONAT1±9

ARRANGEMENT OF COMPONENTS
 No. Components Function
 
1Pattern Select Switch Selects the Manual mode or the Normal mode for shift 1 Pattern Select Switch Selects the Manual mode or the Normal mode for shift
and lock±up timing. 
2Crankshaft Position SensorDetects the engine speed 2 Crankshaft Position Sensor Detects the engine speed.
 3Park/Neutral Position SwitchDetects the shift lever position

3 Park/Neutral Position Switch Detects the shift lever position.
 
4Stop Light SwitchDetects if the brake pedal is depressed 4 Stop Light Switch Detects if the brake pedal is depressed.
5Throttle Position SensorDetects the throttle valve opening angle 5 Throttle Position Sensor Detects the throttle valve opening angle.
 
6O/D Main Switch Prevents up±shift to the O/D gear if the O/D main 6 O/D Main Switch Prevents u shift to the O/D gear if the O/D main
switch is off.
 
 7Cruise Control ECU
This ECU prevents the transmission from shifting into
O/D and prohibits lock up control when the vehicle's 7 Cruise Control ECU O/D and prohibits lock±up control when the vehicle's
speed drops below the cruise control set speed parameter.
AT1±10± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATION

 
 
 
8
 
 
 
No.1 and No.2 Vehicle Speed Sensor
 
 
 
Detects the vehicle speed. Ordinarily, transmission control
uses signals from the No.2 vehicle speed sensor, and the
No.1 vehicle speed sensor is used as a back±up.
 9Engine Coolant Temp SensorDetects the engine coolant temp 9Engine Coolant Temp. SensorDetects the engine coolant temp.
 
10ECMControls the engine and transmission actuators based on 10ECMControls the engine and transmission actuators based on
signals from each sensor. 
 11No 1 and No 2 Solenoid ValvesControl the hydraulic pressure applied to each shift valve,
 11No.1 and No.2 Solenoid ValvesControl the hydraulic ressure a lied to each shift valve,
and control the gear position and timing.
 
12
Lock±up Solenoid Valve
(For lock up control pressure modulaControls the hydraulic pressure applied to the lock±up 
 
12(For lock±up control pressure modula-
tion)Controls the hydraulic ressure a lied to the lock u
clutch and controls lock±up timing.
 
13O/D OFF Indicator Light
Blinks and warns the driver, while the O/D main switch is
pushed in when the electronic control circuit is malfunction 
 
13O/D OFF Indicator Lightpushed in, when the electronic control circuit is malfunction-
ing.
 
14Kick down SwitchDetects if the accelerator pedal is depressed beyond the 14Kick±down SwitchDetects if the accelerator edal is de ressed beyond the
full throttle valve opening position.
 
15A/T Fluid Temp SensorDetects the A/T fluid temp 15A/T Fluid Temp. SensorDetects the A/T fluid temp.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONOPERATIONAT1±11

09032±00100 Oil Pan Seal Cutter
09308±10010 Oil Seal Puller
09325±40010 Transmission Oil Plug
09350±30020 TOYTOA Automatic Transmission
Tool Set
(09351±32010) One±way Clutch Test Tool
(09351±32020) Stator Stopper
09843±18020 Diagnosis Check Wire
09990±01000 Engine Control Computer Check
Harness ªAº
09992±00094 Automatic Transmission Oil
Pressure Gauge Set
PRECAUTION
PRECAUTIONS
When working with FIPG material, you must observe the following.
wUsing a razor blade and gasket scraper, remove all the old packing (FIPG) material from the
gasket surfaces.
wThoroughly clean all components to remove all the loose material.
wClean both sealing surfaces with a non±residue solvent.
wApply the seal packing in an approx. 1 mm (0.04 in.) bead along the sealing surface.
wParts must be assembled within 10 minutes of application. Otherwise, the packing (FIPG)
material must be removed and reapplied.
If the vehicle is equipped with a mobile communication system, refer to the precaution in the IN sec-
tion.
PREPARATION
SST (SPECIAL SERVICE TOOLS)
AT1±12± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONPRECAUTION

RECOMMENDED TOOLS
09082±00050 TOYTOA Electrical Tester Set
EQUIPMENT
 
 Vernier calipers 
 Check torque converter clutch
installation.
 
Dial indicator with magnetic baseCheck drive plate runout. Dial indicator with magnetic baseCheck drive late runout.
 
 Straight edgeCheck torque converter clutch
installation.
 
To rque wrench Torque wrench
LUBRICANT
 Item Capacity Classification
 Automatic transmission fluid
Dry fill7 2 liter (7 6 US qts 6 3 lmpqts)ATF DEXRON[II 
 
Dry fill
Drain and refill
7.2 liter (7.6 US qts, 6.3 lmp.qts)
1.6 liter (1.7 US qts, 1.4 lmp.qts)
ATF DEXRON[ II
SSM (SPECIAL SERVICE MATERIALS)
 
 
 
088260±0090 
 
 
Seal Packing 1281.
THREE BOND 1281 or equivalent
(FIPG) 
 
 
Transmission X Oil pan
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONPREPARATIONAT1±13

ON±VEHICLE REPAIR
NO.1 VEHICLE SPEED SENSOR
ASSEMBLY REPLACEMENT
1. DISCONNECT NO.1 VEHICLE SPEED SENSOR
CONNECTOR
2. REMOVE NO.1 VEHICLE SPEED SENSOR ASSEMBLY
(a) Remove the bolt and No.1 vehicle speed sensor assembly.
(b) Remove the speedometer driven gear from the No.1 vehicle
speed sensor.
(c) Remove the O±ring from the No.1 vehicle speed sensor.
3. INSTALL NO.1 VEHICLE SPEED SENSOR ASSEMBLY
(a) Coat a new O±ring with A/T fluid and install it to the No.1
vehicle speed sensor.
(b) Install the speedometer driven gear to the No.1 vehicle
speed sensor.
(c) Install the No.1 vehicle speed sensor to the extension
housing and torque the bolt.
Torque: 16 NVm (160 kgfVcm, 12 ftVlbf)
4. CONNECT NO.1 VEHICLE SPEED SENSOR
CONNECTOR
NO.2 VEHICLE SPEED SENSOR
REPLACEMENT
1. DISCONNECT NO.2 VEHICLE SPEED SENSOR
CONNECTOR
2. REMOVE NO.2 VEHICLE SPEED SENSOR
(a) Remove the bolt and No.2 vehicle speed sensor.
(b) Remove the O±ring.
3. INSTALL NO.2 VEHICLE SPEED SENSOR
(a) Coat a new O±ring with A/T fluid and install it to the No.2
vehicle speed sensor.
(b) Install the No.2 vehicle speed sensor to the extension
housing and torque the bolt.
Torque: 5.4 NVm (55 kgfVcm, 48 in.Vlbf)
4. CONNECT NO.2 VEHICLE SPEED SENSOR
CONNECTOR AT1±14
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONON±VEHICLE REPAIR