1995 TOYOTA SUPRA brake light

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

Connect a voltmeter to the terminals TT and
E1 of the DLC2.
Turn ignition switch ON (Do not start the en-
gine).
Fully depress the accelerator pedal until the
voltmeter indicates 8 V and hold it.
Depress and release the brake pedal and
check the voltage.
Check stop light signal.
Brake pedal
Proceed to next circuit inspection shown on
matrix chart (See page AT1±58).
Check harness and connector between ECM and stop light switch
(See page IN±30).
Repair or replace harness or connector
Voltage
Depressed0 V
Released8 V
Check and replace ECM. AT1±84
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

LOCK±UP POINT
NORM Mode
 
 
D position km/h (mph)
Throttle valve opening 5% 
 Lock±up ON
 
 Lock±up OFF
 3rd Gear (O/D switch OFF) 56±62 (35±39) 53±59 (35±39)
 O/D Gear 56±62 (35±39) 53±59 (35±39)
MANU Mode
 
 D position km/h (mph)
Throttle valve opening 5%
 
 Lock±up ON
 
 Lock±up OFF
 
 3rd Gear (O/D switch OFF)
 
 98±105 (61±65)
 
 92±99 (57±62)
 O/D Gear 163±175 (101±109) 56±62 (35±39)
HINT:
(1) There is no lock±up in the 2 and L positions.
(2) In the following cases, the lock±up will be released regardless of the lock±up pattern.
w When the throttle valve is completely closed.
w When 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 63 km/h (39 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.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONSERVICE SPECIFICATIONSAT1±97

ARRANGEMENT OF COMPONENTS
ComponentsFunction 
 Pattern Select Switch
 
 Selects the Power mode or the Normal mode for shift and
lock±up timing.
 
 Crankshaft Position Sensor and Camshaft Position
Sensor 
 Detects the engine speed.
 Park/Neutral Position Switch Detects the shift lever position.
 Stop Light Switch Detects if the brake pedal is depressed.
 Throttle Position Sensor Detects the throttle valve opening angle.
 O/D Main Switch Prevents up±shift to the O/D gear if the O/D switch is off.
 
 
 
Cruise Control ECU
 
 
 
This ECU prevents the transmission from shifting into O/D
and prohibits lock±up control when the vehicle's speed
drops below the cruise control set speed parameter.
 
 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.
AT2±10± 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

Vehicle Brought to Workshop
Customer Problem Analysis
P. AT2±33
Check and Clear Diagnostic Trouble Codes (Precheck)
P. AT2±34 ~AT2±35
Problem Symptom Confirmation
P. AT2±37
Symptom Simulation
P. IN±24
Diagnostic Trouble Code Check
P. AT2±34 ~AT2±35
Preliminary Check
P. AT2±42
Diagnostic Trouble Code Check
P. AT2±54
Shift Position Signal Check
P. AT2±36
Mechanical System Tests
P. AT2±44
Manual Shifting Test
P. AT2±53
Items insideare titles of pages in this manual,
with the page number indicated in the bottom portion.
See the indicated pages for detailed explanations.
Step [2], [5], [12], [15]:
Diagnostic steps permitting the use of the TOYOTA hand±
held tester or TOYOTA brake±out box.
Matrix Chart of Problem Symptoms ± P. AT2±62
Chapter 1
(Electronic)Chapter 2
(On±Vehicle)Chapter 3
(OFF±Vehicle)
P. AT2±66P. AT2±64
Circuit
Inspection
Main Throttle Signal Check

Stop Light Signal Check

Kick±Down Signal Check
P. AT2±68
Parts Inspection
P. AT2±70 ~AT2±115
Identification of ProblemRepairConfirmation TestEND
HOW TO PROCEED WITH TROUBLESHOOTING
AT2±32± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

CHECK TERMINAL TT OUTPUT
VOLTAGE
When a voltmeter is connected to the DLC2, the following
items can be checked.
1. Throttle position sensor signal
2. Brake signal
3. Shift position signal
1. VOLTMETER CONNECTION
Connect the positive (+) probe of the voltmeter to terminal TT
and the negative (±) probe to terminal E1 of the DLC2.
HINT: If a voltmeter with small internal resistance is used, the
correct voltage will not be indicated, so use a voltmeter with
an internal resistance of at least 10 k
/V.
2. TURN IGNITION SWITCH TO ON (DO NOT START THE
ENGINE)
3. CHECK THROTTLE POSITION SENSOR SIGNAL
Check if the voltage changes from approx. 0 V to approx. 8
V when the accelerator pedal is gradually depressed from the
fully closed position.
4. CHECK BRAKE SIGNAL (LOCK±UP CUT SIGNAL)
(a) Open the throttle valve fully to apply approx. 8 V to terminal
TT.
(b) In this condition, check terminal TT voltage when the brake
pedal is depressed and released.
TT terminal voltage:
0 V (When brake pedal is depressed)
8 V (When brake pedal is released)
5. START ENGINE
6. CHECK SHIFT POSITION SIGNAL
(VEHICLE SPEED ABOVE 10 km/h, 6 mph)
Check up±shifting together with terminal TT voltage.
 Gear Position Terminal TT output voltage 1st Gear 0 V 
 2nd Gear
 
 2 V
 3rd Gear 4 V
 3rd Lock±up 5 V
 O/D 6 V
 O/D Lock±up 7 V
HINT: Check for light shocks from up±shifting and for
changes in the tachometer.
If terminal TT Output voltage check cannot be done, do the
check of TT terminal circuit on page AT2±115. AT2±36
± A340E (2JZÐGTE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

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