1995 TOYOTA SUPRA turn signal

Blinking Light FRS Pressure Switch Circuit
CIRCUIT DESCRIPTION
The pressure switch sends the appropriate signals to the A/C amplifier when the air conditioning refrig-
erant pressure drops too low or rises too high. When the A/C amplifier receives these signals, it outputs
signals via the ECM to switch OFF the compressor relay and turns the magnetic clutch OFF.
Diagnostic Sensor Check Detecting ConditionTrouble Area

Pressure switch

Harness or connector between pressure switch
and A/C amplifier

Refrigerant pipe line

A/C amplifierOpen in pressure sensor circuit
Abnormal refrigerant pressure
below 196 kPa (2.0 kgf/cm2, 28 psi)
over 3,140 kPa (32.0 kgf/cm2, 455 psi)
AC±40± AIR CONDITIONING SYSTEMTROUBLESHOOTING

Blinking Light HI Air Outlet Damper Control Servo Motor Circuit
CIRCUIT DESCRIPTION
This circuit turns the servo motor and changes each mode damper position by the signals from the A/C
amplifier. When the AUTO switch is on, the A/C amplifier changes the mode automatically between
(FACE), (BI±LEVEL) and (FOOT) according to the temperature setting.
Trouble AreaDiagnostic Sensor Check Detecting Condition

Air outlet damper control servo motor

Air outlet damper position sensor

Harness or connector between A/C amplifier and
air outlet damper control servo motor, air outlet
damper position sensor

A/C amplifier Air outlet damper position sensor value does not
change even if A/C amplifier signals the air outlet
damper control servo motor.
AC±50± AIR CONDITIONING SYSTEMTROUBLESHOOTING

Compressor Circuit
CIRCUIT DESCRIPTION
The A/C amplifier outputs the magnetic clutch ON signal from terminal MGC to the ECM. When the ECM re-
ceives this signal, it sends a signal from terminal ACMG and switches the air conditioning magnetic clutch relay
ON, thus turning the air conditioning compressor magnetic clutch ON.
AC±62± AIR CONDITIONING SYSTEMTROUBLESHOOTING

INSPECTION PROCEDURE
Check voltage of TSET terminal on A/C amplifier.
Check voltage of terminal on A/C control assembly.
Check harness and connectors for S5 and SG signal.
Proceed to next circuit inspection shown on
matrix chart (See page AC±26).
Replace A/C control assembly.
Repair or replace harness or connectors between
A/C amplifier and A/C control assembly.
Repair or replace harness or connectors between
A/C amplifier and A/C control assembly.
VoltageCheck Terminals
VoltageSet Temperature
1. Turn temperature set dial.
2. Check voltage between terminals TSET and SG
of A/C amplifier.
Remove A/C amplifier with connectors still connected.
Remove A/C control assembly with connectors still
connected.
Check voltage between following terminal and H12±9
(GND) of A/C control assembly connectors.
AC±70± AIR CONDITIONING SYSTEMTROUBLESHOOTING

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(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.

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