1995 TOYOTA SUPRA brake sensor

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

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

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 9 km/h, 6 mph)
Check up±shifting together with terminal TT voltage.
HINT: Check for light shocks from up±shifting and for
changes in the tachometer.
 
 Gear Position
 
 Terminal TT output voltage
1st Gear0V 1st Gear0 V
2nd Gear2V 2nd Gear2 V
 2nd Lock up3V2nd Lock±up3 V 
3rd Gear4V 3rd Gear4 V
3rd Lock up5V 3rd Lock±up5 V
O/D6V O/D6 V
 O/D Lock up7VO/D Lock±up7 V
If terminal TT output voltage check cannot be done, do the
check of TT terminal circuit on page AT1±95. AT1±36
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

INSPECTION PROCEDURE
(See page EG±219).
Turn ignition switch ON.
Do not depress the brake pedal during this test.
The voltage will stay at 0 V if depressed.
Voltage changes from 0 V to 8 V by stages.
Check throttle position signal.
Check voltage at the terminal TT of the DLC2
while gradually depressing the accelerator pedal
from the fully closed position to the fully opened
position.
Proceed to next circuit inspection shown on
matrix chart (See page AT1±58).
Replace throttle position sensor.
Repair or replace harness or connector.
Check and replace ECM.
Check harness and connector between ECM and throttle position sen-
sor (See page IN±30).
AT1±78± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

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

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

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