1995 TOYOTA SUPRA sensor

(See page IN±30).
(See page IN±30).
(See page BR±62).
Remove front fender splash shield.
Disconnect speed sensor connector.
Measure resistance between terminals 1 and 2 of
speed sensor connector.
Resistance: 0.7 ± 1.7 k

Resistance: 1 M
or higher
Remove rear seat cushion, seat back and quarter
trim panel.
Disconnect speed sensor connector.
Measure resistance between terminals 1 and 2 of
speed sensor connector.
Resistance: 0.7 ± 1.7 k

Measure resistance between terminals 1 and 2 of
speed sensor connector and body ground.
Resistance: 1 M
or higher
Repair or replace harness or connector.
Check speed sensor.
Check for open and short in harness and connector between terminals FRO,
FLO, RRO, RLO of ABS & TRAC ECU and TRAC ECU (See page IN±30).
Front
Rear
Replace speed sensor.
NOTICE: Check the speed sensor signal last (See page BR±62).
Check for open and short in harness and connector between each speed
sensor and ECU (See page IN±30).
Repair and replace harness or connector.
INSPECTION PROCEDURE
HINT: If the same code is output from the ABS warning light, troubleshoot the ABS first. BR±140
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)

(See page SA±15).
(See page SA±45).
Remove front speed sensor rotor
(See page SA±15).
Check sensor rotor serrations.
No scratches or missing teeth.
Check the front speed sensor installation.
The installation bolt is tightened properly.
Remove the drive shaft (See page SA±45).
Check the sensor rotor serrations.
No scratches or missing teeth.
Front
Rear
Check sensor rotor and sensor installation.
Check the rear speed sensor installation.
The installation bolt is tightened properly and
there is no clearance between the sensor and rear
axle carrier.
Replace speed sensor or rotor.
Check and replace ABS (& TRAC) ECU.
NOTICE: Check the speed sensor signal last (See page BR±62).
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±141

DTC 45 46 Main Throttle Position Sensor Circuit
CIRCUIT DESCRIPTION
This circuit is not directly related to the TRAC control, but as it has an influence on TRAC control when trouble
occurs in this circuit, it is used to switch off the TRAC system as a fail safe function.
 
 DTC No. 
 Diagnostic Trouble Code Detecting Condition 
 Trouble area
 
 
 
 
45
 
 
 
 
Conditions (1) and (2) continue for 0.31 sec.:
(1) CTP switch of main throttle position sensor is ON.
(2) Input voltage of ECM terminal VTA1:
1.5 V or more. 
 
 
 

Main throttle position sensor

Short in IDL1 circuit

ECM

TRAC ECU
 
 
 
 
 
46
 
 
 
 
 
Either of the following (1) or (2) continues for
0.6 sec.:
(1) Input voltage of ECM terminal VTA1:
4.9 V or more.
(2) Input voltage of ECM terminal VTA1:
0.1 V or less. 
 
 
 
 

Main throttle position sensor

Open or short in VTA1 circuit

ECM
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±149

INSPECTION PROCEDURE
HINT: The main throttle position sensor signal is transmitted to the TRAC ECU from ECM, so if an error occurs
at the engine side, the TRAC ECU also detects it.
If diagnostic trouble code No.41 is being output for the engine troubleshoot the engine first.
Remove TRAC ECU with connectors still con-
nected.
Disconnect the vacuum hose from the throttle
opener, and apply the vacuum to the throttle open-
er.
Is diagnostic trouble code output for the engine?
Turn ignition switch ON.
Measure voltage between terminal IDL1 of TRAC ECU
and body ground, when the main throttle valve is fully clo-
sed and fully open.
Main throttle valve position
Fully closed
Check voltage between terminal IDL1 of TRAC ECU and body ground.
Fully open
Voltage
Below 1.0 V
10 ± 14 V
Do diagnostic trouble code check on page EG±491.
Repair circuit indicated by the code output.
BR±150± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)

(See page IN±30).
page IN±30).
(See
(See page IN±30).
(See page EG±554).
Check for open and short in harness and connector between terminal IDL1
of TRAC ECU and main throttle position sensor with TRAC ECU, ECM and
main throttle position sensor connectors disconnected (See page IN±30).
Check voltage of terminal VTA1 of ECM (See page EG±554).
Repair or replace harness or connector.
Check for short in harness between terminal IDL1 of TRAC ECU and body
ground with only main throttle position sensor connector connected (See
page IN±30).
Check and replace main throttle position
sensor.
Check and replace ECM.
Check and replace TRAC ECU.
Check for short in harness between terminal IDL1 of TRAC ECU and body
ground with only ECM connector connected (See page IN±30).
Check for open and short in harness and connector between terminal
VTA1 of ECM and main throttle position sensor (See page IN±30).
Check main throttle position sensor (See page EG±555).
Check and replace ECM.
Repair or replace harness or connector.
Adjust or replace main throttle position sensor
See page EG±292).
Check and replace ECM.
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±151

DTC 47 48 Sub±Throttle Position Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the opening angle of the sub±throttle valve and sends the appropriate signals to the ECU.
If a trouble signal is input, the ECU prohibits TRAC control.
 
 DTC No. 
 Diagnostic Trouble Code Detecting Condition 
 Trouble area
 
 
 
 
 
 
 
 
47
 
 
 
 
 
 
 
 
When any of the following (1) through (3) is
detected:
(1) Deviation of 5 steps or more to the closed side of
the idle step during sub±throttle initial check.
(2) Voltage at terminal IDL2 does not
become 0 V even after sub±throttle is driven to fully
closed position during sub±throttle initial check.
(3) Voltage at terminal VTA2 of ECM is 1.5 V or more
for at least 0.31 sec. while CTP switch is ON. 
 
 
 
 
 
 
 

Sub±throttle position sensor

Open or short in IDL2 circuit

ECM

TRAC ECU
 
 
 
 
 
 
48
 
 
 
 
 
 
Either of the following (1) or (2) continues for
at least 0.26 sec.:
(1) Input voltage of ECM terminal VTA2:
4.9 V or more
(2) Input voltage of ECM terminal VTA2:
0.1 V or less. 
 
 
 
 
 

Sub±throttle position sensor

Open or short in VTA2 circuit

ECM
BR±152± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)

INSPECTION PROCEDURE
HINT: The sub±throttle position sensor signal is transmitted to the TRAC ECU from ECM, so if an error occurs
at the engine side, the TRAC ECU also detects it.
If diagnostic trouble code No. 47 is being output for the engine, troubleshoot the engine first.
Check voltage between terminal IDL2 of TRAC ECU and body ground.
Remove TRAC ECU with connectors still con-
nected.
Remove intake air duct.
Disconnect step motor connector.
Repair circuit indicated by the code output.
Do diagnostic trouble code check on page EG±491.
Is diagnostic trouble code output for the engine?
Turn ignition switch ON.
Measure voltage between terminal IDL2 of TRAC ECU
and body ground, when the sub±throttle valve is fully
closed and fully open.
Go to step 6.
Engine condition
Sub±throttle valve position
Fully open
Voltage
Below 1.0 V
10 ± 14 V
Fully closed
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±153

(See page IN±30).
(See page IN±30).
(See page IN±30).
(See page EG±294).
Check for open and short in harness and connector between terminal IDL2
of TRAC ECU and main throttle position sensor with TRAC ECU, ECM and
main throttle position sensor connectors disconnected (See page IN±30).
Check voltage of terminal VTA2 of ECM (See page EG±554).
Repair or replace harness or connector.
Check for short in harness between terminal IDL2 of TRAC ECU and body
ground with only main throttle position sensor connector connected (See
page IN±30).
Check and replace main throttle position sensor.
Check and replace ECM.
Check and replace TRAC ECU.
Check for short in harness between terminal IDL2 of TRAC ECU and body
ground with only ECM connector connected (See page IN±30).
Check for open and short in harness and connector between terminal
VTA2 of ECM and main throttle position sensor (See page IN±30).
Check main throttle position sensor (See page EG±555).
Check and replace ECM.
Repair or replace harness or connector.
Adjust or replace main throttle position sensor
See page EG±294).
Check and replace ECM.
BR±154± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)