1995 TOYOTA SUPRA coolant

ELECTRONIC CONTROL SYSTEM
The electronic control system for the A340E automatic transmission provides extremely precise control of
the gear shift timing and lock±up timing in response to driving conditions as sensed by various sensors
located throughout the vehicle and in response to the engine's running condition.
At the same time, the ECM control reduces vehicle squat when the vehicle starts out and gear shift shock.
The electronic control system is also equipped with a self diagnosis system which diagnoses malfunctions
for the vehicle to continue functioning when a malfunction occurs.
CONSTRUCTION
The electronic control system can be broadly divided onto three groups; the sensors, ECM and actuators.
No. 1 Vehicle Speed Sensor
No. 2 Vehicle Speed Sensor
Crankshaft Position Sensor
Camshaft Position Sensor No.1, No.2
Park/Neutral Position Switch

Neutral Start Signal

Shift lever Position Signal

Idling Signal

Throttle Position Signal
Main (Sub) Ð throttle Position Sensor
Engine Coolant temp. Sensor
A/T Fluid Temp. Sensor
O/D Main Switch
Cruise Control ECU
Kick±Down Switch
Stop Light Switch
Pattern Select Switch
SENSORSECMACTUATORS
No.1 Solenoid Valve
No.2 Solenoid Valve
No.3 Solenoid Valve
No.4 Solenoid Valve
No.5 Solenoid Valve
Engine Torque Control (ESA)
Igniters
Ignition Coils
Distributors
Spark Plugs
O/D OFF Indicator Light
(Diagnostic Trouble Code
Display)
TRAC ECU
O/D Direct Clutch Speed Sensor
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONOPERATIONAT2±7

 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

PROBLEM SYMPTOM CONFIRMATION
Taking into consideration the results of the customer problem analysis, try to reproduce the symptoms of
the trouble. If the problem is that the transmission does not up±shift, does not down±shift, or the shift point
is too high or too low, conduct the following road test to confirm the automatic shift schedule and simulate
the problem symptoms.
ROAD TEST
NOTICE: Do the test at normal A/T fluid operating temp.
50±805C (122±1765F).
1. D POSITION TEST (NORM PATTERN)
Shift into the D position and keep the accelerator pedal
constant at the full throttle valve opening position, and check
the following points:
(a) Check up±shift operation.
Check that 1±2, 2±3 and 3±O/D up±shift takes place, at the
shift point shown in the automatic shift schedule.
(See page AT2±116)
HINT:
(1) O/D Gear Up±shift Prohibition Control.
wCoolant temp. is 605C (1405F) or less.
wIf there is a 10 km/h (6 mph) difference between the set
cruise control speed and vehicle speed.
wO/D main switch is pushed ON.
`(During O/D OFF, indicator light lights up.)
(2) O/D Gear Lock±up Prohibition Control.
wBrake pedal is depressed.
wCoolant temp. is 605C (1405F) or less.
(b) Check for shift shock and slip.
Check for shock and slip at the 1±2, 2±3, and 3±O/ D up±
shifts.
(c) Check for abnormal noise and vibration.
Run at the D position lock±up or O/D gear and check for ab-
normal noise and vibration.
HINT: The check for the cause of abnormal noise and vibra-
tion must be performed very thoroughly as it could also be
due to loss of balance in the, torque converter clutch, etc.
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT2±37

(d) Check kick±down operation.
While running in the D position, 2nd, 3rd and O/D gears,
check to see that the possible kick±down vehicle speed limits
for 2
" 1, 3 " 2 and O/D " 3 kick±downs conform to those
indicated on the automatic shift schedule.
(See page AT2±116)
(e) Check for abnormal shock and slip at kick±down.
(f) Check the lock±up mechanism.
(1) Drive in D position, O/D gear, at a steady speed (lock±up
ON) of about 59 km/h (37 mph).
(2) Lightly depress the accelerator pedal and check that the
RPM does not change abruptly.
If there is a big jump in RPM, there is no lock±up.
2. D POSITION TEST (MANU PATTERN)
Shift into the D position and hold the accelerator pedal
constant at the full throttle valve opening position, and check
the following points:
(a) Check up±shift operation.
2±3 and 3±O/D up shifts should take place, and shift points
should conform to those shown in the automatic shift sched-
ule.
(See page AT2±116)
HINT:
wO/D up±shift or lock±up will not occur when the engine
coolant temp. is below 605C (1405F) and speed is under
60 km/h (37 mph), or if there is a 10 km/h (6 mph)
difference between the set cruise control speed.
w3rd up±shift or lock±up will not occur when engine
coolant temp. is 355C (955F) and speed is under 40 km/h
(25 mph).
(b) Check for shift shock and slip.
In the same manner, check the shock slip at the 2
" 3 and
3
" O/D up±shifts. AT2±38
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

AT2±101AT2±99AT2±103AT2±105AT2±108AT2±111EG±312AT2±60AT2±66AT2±68AT2±92BR±128AT2±70
Park/neutral position
switchPattern select switch
circuitStop light switch
circuitKick±down switch
circuitO/D switch O/D OFF
indicator light circuitEngine coolant temp.
sensor circuitO/D cancel signal
circuitECMNo.5 solenoid
circuitOFF±Vehicle repair
matrix chartOn±Vehicle repair
matrix chartTRAC ECUA/T fluid temp.
sensor circuit
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT2±65

LOCK±UP POINT
NORM Mode
 D position Throttle valve opening 5% Lock±up ON km/h (mph) Lock±up OFF km/h (mph)
 3rd Gear 60±66 (37±41) 50±56 (31±35)
 O/D Gear 53±59 (33±37) 50±56 (31±35)
MANU Mode
 D position Throttle valve opening 5% Lock±up ON km/h (mph) Lock±up OFF km/h (mph) 
2nd Gear (2 position) 
60±66 (37±41) 
57±63 (35±39) 
 3rd Gear (D position)
 
 60±66 (37±41)
 
 57±63 (35±39)
 O/D Gear (D position) 181±195 (112±121) 69±76 (43±47)
HINT:
(1) There is no lock±up in the L positions.
(2) In the following cases, the lock±up will be released regardless of the lock±up pattern.
wWhen the throttle valve is completely closed.
wWhen the brake light switch is ON.
(3) Shift up to 3rd will not occur when the engine coolant temp. is below 35°C (95°F) and the vehicle
speed is below 40 km/h (25 mph).
(4) Shift±up to O/D will not occur when the engine coolant temp. is below 60°C (140°F) and the vehicle
speed is below 60 km/h (37 mph).
(5) When the vehicle speed drops to 10 km/h (6 mph) or more below the cruise control set vehicle speed,
shift down from O/D to 3rd occurs.
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONSERVICE SPECIFICATIONSAT2±117

TROUBLESHOOTING
The table below will be useful for you in troubleshooting these electrical problems. The most likely causes
of the malfunction are shown in the order of their probability. Inspect each part in the order shown, and
replace the part when it is found to be faulty.
METER, GAUGES AND ILLUMINATION
 Trouble Parts name (See page)
 
 
 
Tachometer, Fuel Gauge and Engine Coolant Tempera-
ture Gauge do not operate
 
 
 
1. GAUGE Fuse (BE±6)
2. Meter Circuit Plate (BE±44)
3. Wire Harness
 
 
 
Speedometer does not operate
 
 
 
1. Vehicle Speed Sensor (BE±46)
2. Meter Circuit Plate (BE±44)
3. Wire Harness
 
 
 
 
Tachometer does not operate
 
 
 
 
1. Igniter
2. ECM (EG Section)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
 
Fuel Gauge does not operate or abnormal operation
 
 
 
 
1. Fuel Receiver Gauge (BE±48)
2. Fuel Sender Gauge (BE±49)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
 
Engine Coolant Temperature Gauge does not operate or
abnormal operation
 
 
 
 
1. Engine Coolant Temperature Receiver Gauge (BE±50)
2. Engine Coolant Temperature Sender Gauge (BE±50)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
 
All illumination lights do not light up
 
 
 
 
1. TAIL Fuse (BE±6)
2. Light Control Rheostat (BE±54)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
Only one illumination light does not light up 
 
1. Bulb
2. Meter Circuit Plate (BE±44)
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±41

ENGINE COOLANT TEMPERATURE
GAUGE INSPECTION
1. INSPECT RECEIVER GAUGE OPERATION
(a) Disconnect the connector from the sender gauge.
(b) Turn the ignition switch ON, check that the receiver gauge
needle indicates COOL.
(c) Ground terminal on the wire harness side connector through
a 3 W test bulb.
(d) Turn the ignition switch ON, check that the bulb lights up and
the receiver gauge needle moves toward the hot side.
If operation is as specified, replace the sender gauge.
Then recheck the system.
If operation is not as specified, measure the receiver gauge
resistance.
2. INSPECT RECEIVER GAUGE RESISTANCE
Measure the resistance between terminals.
HINT: Connect the test leads so that the current from the
ohmmeter can flow according to the chart order.
 Between terminals Resistance (
) 
A±B 
Approx. 229.7
 A±C Approx. 54.0
 B±C Approx. 175.7
If resistance value is not as specified, replace the engine
coolant temperature receiver gauge.
3. INSPECT SENDER GAUGE RESISTANCE
Measure the resistance between terminal and gauge body.
 Temperature °C (°F) Resistance (
)
 50 (122.0) 160 ~ 240
 120 (248.0) 17.1 ~ 21.2
If resistance value is not as specified, replace the engine
coolant temperature sender gauge. BE±50
± BODY ELECTRICAL SYSTEMCOMBINATION METER