brakes TOYOTA SUPRA 1995 Service Repair Manual

A340E (2JZ-GTE) AUTOMATIC TRANSMISSIONOPERATION -
AT-7
3. HYDRAULIC CONTROL SYSTEM
The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accu-
mulators, 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 hy-
draulic pressure acting on the torque converter clutch, clutches and brakes in accordance with the ve-
hicle driving conditions.
There are 5 solenoid valves on the valve body.
The No.1 and No.2 solenoid valves are turned on and off by signals from the ECM to control the shift
valves, and change the gear shift position.
The No.3 solenoid valve is operated by signals from the ECM to engage or disengage the lock-up
clutch of the torque converter clutch.
The No.4 solenoid valve is operated by signals from the ECM to control the engagement speed and
reduce gear shift shock.
The No.5 solenoid valve is operated by signals from the ECM to regulate the line pressure to throttle
pressure.

A340E (2JZ-GTE) AUTOMATIC TRANSMISSIONCOMPONENT PARTS --
AT-27
COMPONENT PARTS
GENERAL NOTES
The instructions here are organized so that you work on only one component group at a time.
This will help avoid confusion from similar-looking parts of different subassemblies being on your work-
bench at the same time.
The component groups are inspected and repaired from the converter housing side.
As much as possible, complete the inspection, repair and assembly before proceeding to the next compo-
nent group. If a component group cannot be assembled because parts are being ordered, be sure to keep
all parts of that group in a separate container while proceeding with disassembly, inspection, repair and
assembly of other component groups.
Recommended ATF:
Type T-II or equivalent
GENERAL CLEANING NOTES:
1. All disassembled parts should be washed clean and any fluid passages and holes blown through with
compressed air.
2. When using compressed air to dry parts, always aim away from yourself to prevent accidentally spray-
ing automatic transmission fluid or kerosene on your face.
3. The recommended automatic transmission fluid or kerosene should be used for cleaning.
PARTS ARRANGEMENT:
1. After cleaning, the parts should be arranged in the correct order to allow efficient inspection, repairs,
and reassembly.
2. When disassembling a valve body, be sure to keep each valve together with the corresponding spring.
3. New discs for the brakes and clutches that are to be used for replacement must be soaked in transmis-
sion fluid for at least 15 minutes before assembly.
GENERAL ASSEMBLY:
1. All oil seal rings, clutch discs, clutch plates, rotating parts, and sliding surfaces should be coated with
transmission fluid prior to reassembly.
2. All gaskets and rubber O-rings should be replaced.
3. Make sure that the ends of a snap ring are not aligned with one of the cutouts and are installed in the
groove correctly.
4. If a worn bushing is to be replaced, the subassembly containing that bushing must also be replaced.
5. Check thrust bearings and races for wear or damage. Replace if necessary.
6. Use petroleum jelly to keep parts in place.
AT0DD-03

A340E(Others) AUTOMATIC TRANSMISSIONOPERATION -
AT-8
3. 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 pres-
sure acting on the torque converter clutch, clutches and brakes in accordance with the vehicle driving
conditions.
There are 3 solenoid valves on the valve body.
The No.1 and No.2 solenoid valves are turned on and off by signals from the ECM to operate the shift
valves and change the gear shift position.
The lock-up solenoid valve is operated by signals from the ECM to engage or disengage the lock-up
clutch of the torque converter clutch.

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 effort required of 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 prob-
lems are noted, the line pressure should be measured to see if it is within specification.

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, the line pressure is regulated according to
the throttle valve opening.
In the hydraulically controlled automatic transmission, throttle pressure is used for regulating line pres-
sure and as signal pressure for up-shift and down-shift of the transmission. In the electronically con-
trolled 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.

A340E(Others) AUTOMATIC TRANSMISSIONCOMPONENT PARTS -
AT-38
COMPONENT PARTS
General Notes
The instructions here are organized so that you work on only one component group at a time.
This will help avoid confusion from similar-looking parts of different subassemblies being on your work-
bench at the same time.
The component groups are inspected and repaired from the converter housing side.
As much as possible, complete the inspection, repair and assembly before proceeding to the next compo-
nent group. If a component group cannot be assembled because parts are being ordered, be sure to keep
all parts of that group in a separate container while proceeding with disassembly, inspection, repair and
assembly of other component groups.
Recommended ATF:
DEXRON® II
GENERAL CLEANING NOTES:
1. All disassembled parts should be washed clean and any fluid passages and holes blown through with
compressed air.
2. When using compressed air to dry parts, always aim away from yourself to prevent accidentally spray-
ing automatic transmission fluid or kerosene in your face.
3. The recommended automatic transmission fluid or kerosene should be used for cleaning.
PARTS ARRANGEMENT:
1. After cleaning, the parts should be arranged in the correct order to allow efficient inspection, repairs,
and reassembly.
2. When disassembling a valve body, be sure to keep each valve together with the corresponding spring.
3. New discs for the brakes and clutches that are to be used for replacement must be soaked in transmis-
sion fluid for at least 15 minutes before assembly.
GENERAL ASSEMBLY:
1. All oil seal rings, clutch discs, clutch plates, rotating parts, and sliding surfaces should be coated with
transmission fluid prior to reassembly.
2. All gaskets and rubber O-rings should be replaced.
3. Make sure that the ends of a snap ring are not aligned with one of the cutouts and are installed in the
groove correctly.
4. If a worn bushing is to be replaced, the subassembly containing that bushing must be replaced.
5. Check thrust bearings and races for wear or damage. Replace if necessary.
6. Use petroleum jelly to keep parts in place.
AX0AF-0D

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

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

See
Stop Light Switch Circuit
CIRCUIT DESCRIPTION
The purpose of this circuit is to prevent the engine from stalling, while driving in lock±up condition, when brakes
are suddenly applied.
When the brake pedal is operated, this switch sends a signal to ECM. Then the ECM cancels operation of the
lock±up clutch while braking is in progress.
WIRING DIAGRAM
INSPECTION PROCEDURE
Check operation of stop light.
Check and repair stop light circuit.
Check if the stop lights go on and off normally when the brake pedal is depressed and
released.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±83

TT Terminal Circuit
CIRCUIT DESCRIPTION
Checks of ECM input and output signals related to the throttle position sensor, brakes, shift position and other
circuits can be performed by measuring the voltages at terminal TT of the DLC2
INSPECTION PROCEDURE
Repair or replace harness or connector.
Check and replace ECM.
Check harness and connector between ECM and DLC2 and body ground
(See page IN±30).
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±95

HYDRAULIC CONTROL SYSTEM
The hydraulic control system is composed of an oil pump, valve body, solenoid valves, accumulators,
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 five solenoid valves on the valve body.
The No.1 and No.2 solenoid valves are turned on and off by signals from the ECM to control the shift valves,
and change the gear shift position.
The No.3 solenoid valve is operated by signals from the ECM to engage or disengage the lock±up clutch
of the torque converter clutch.
The No.4 solenoid valve is operated by signals from the ECM to control the engagement speed and reduce
gear shift shock.
The No.5 solenoid valve is operated by signals from the ECM to regulate the line pressure to throttle pres-
sure.
HYDRAULIC CONTROL SYSTEM
VALVE BODY
OIL PUMP
ECMSOLENOID VALVES
CLUTCHES & BRAKES
Hydr. pressure control
Fluid passage switchingPlanetary gear sets
Torque Converter Clutch
AT2±6± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONOPERATION

 O/D Direct Clutch Speed Sensor Detects the input shaft speed from 1st gear to 3rd gear
 Engine Coolant Temp. Sensor Detects the engine coolant temp.
 
 ECM 
 
Controls the engine and transmission actuators based on signals from
each sensor.
 
 No.1 and No.2 Solenoid Valves 
 
Control the hydraulic pressure applied to each shift valve, and control the
gear position and timing.
 
 
 
No.4 Solenoid Valve
(For accumulator back pressure modulation) 
 
 
Controls the hydraulic pressure applied to the back chamber of the accu-
mulator and smoothes the engagement of clutches and brakes during
shifting.
 
 
No.3 Solenoid Valve
(For lock±up control pressure modulation) 
 
Controls the hydraulic pressure applied to the lock±up clutch and controls
lock±up timing.
 
 
No.5 Solenoid Valve
(For line pressure modulation) 
 Controls the line pressure.
 
 O/D OFF Indicator Light 
 
Blinks and warns the driver, while the O/D main switch is pushed in,
when the electronic control circuit is malfunctioning.
 A/T Fluid Temp. Sensor Detects A/T fluid temp.
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONOPERATIONAT2±11