ABS TOYOTA SUPRA 1995 Service Service Manual

Check continuity between each terminal of ABS
motor relay shown below.
Check ABS motor relay.
(1) Apply battery voltage between terminals
(A8) 3 and (A8) 4.
(2) Check continuity between each terminal of
ABS motor relay shown below.
Replace ABS control relay.
Check for open and short in harness and connector between ABS motor
relay and ABS ECU (See page IN±30).
Repair or replace harness or connector.
Terminals
Terminals
3 and
1 and
4
2
Continuity (Reference
value 62
)
Open
Terminals1 and2Continuity
 
 
If the same code is still output after the diagnostic trouble code is deleted, check the contact
condition of each connection.
If the connections are normal, the ECU may be defective.
BR±74± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

Remove ABS motor relay from R/B No. 5.
Measure voltage between terminal 1 of R/B No. 5
(for ABS motor relay) and body ground.
Voltage: 10 Ð 14 V
Check voltage between terminal 1 of R/B No. 5 (for ABS motor relay) and
body ground.
Repair or replace harness or ABS actuator.
Check continuity between terminal 2 of R/B No.5 (for ABS motor relay) and
terminal (A20) 9 of ABS & TRAC ECU.
Check and repair harness or connector.
Check continuity between terminal 2 of R/B No.5
(for ABS motor relay) and terminal (A20) 9 of ABS
& TRAC ECU.
Continuity
HINT: There is a resistance of 4 ~ 6
between ter±
minals (A6) 3 and (A7) 5 of ABS actuator.
INSPECTION PROCEDURE (w/ TRAC)
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)BR±75

Remove motor relay from R/B No. 5.
Check continuity between each pair of terminals of
motor relay shown below.
Check ABS motor relay.
1. Apply battery voltage between terminals
3 and 4.
2. Check continuity between each terminal
shown below.
Terminals 1 and 2Continuity
Terminals 1 and 2Open
Continuity
(Reference value 62
)Terminals 3 and 4
Check for open and short in harness and connector between ABS motor
relay and ABS TRAC ECU (See page IN±30).
 
 
If the same code is still output after the diagnostic trouble code is deleted, check the contact
condition of each connection.
If the connections are normal, the ECU may be defective.
BR±76± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

DTC 15 16 TRAC Solenoid Relay Circuit
CIRCUIT DESCRIPTION
This relay circuit supplies power to each traction actuator solenoid.
When the ignition switch is turned ON, the relay goes on.
 DTC No. Diagnostic Trouble Code Detecting Condition Trouble area 
 
 
 
 
 
 
15
 
 
 
 
 
 
 
Conditions (1) through (3) continue for 0.2
sec. or more:
(1) TRAC solenoid relay terminal (TSR)
voltage: Battery positive voltage
(2) All TRAC actuator solenoids: OFF
(3) All TRAC actuator solenoid monitor
voltages (in ECU): 0 V 
 
 
 
 
 
 

TRAC solenoid relay

Open or short in TRAC solenoid relay circuit

ECU
 
 
 
 
 
 
16
 
 
 
 
 
 
Conditions (1) through (3) continue for 0.2
sec. or more:
(1) TRAC solenoid relay terminal (TSR)
voltage: 0 V
(2) All TRAC actuator solenoids: OFF
(3) TRAC actuator solenoid monitor voltage
(in ECU): Battery positive voltage 
 
 
 
 
 

TRAC solenoid relay

B+ short in TRAC solenoid relay circuit

ECU
Fail safe function: If trouble occurs in this relay circuit, the ECU cuts off current to the ABS and TRAC solenoid
relays and prohibits ABS and TRAC control.
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)BR±77

Remove TRAC solenoid relay from R/B No. 5.
Measure voltage between terminals 1 and 2 of R/B
No. 5 (for TRAC Solenoid relay).
Voltage 10 Ð 14 V
Check voltage between terminals 1 and 2 of R/B No. 5 (for TRAC solenoid
relay).
Check continuity between terminal 3 of R/B No.5
(for TRAC solenoid relay) and terminals (A22) 2
and (A22) 8 of ABS & TRAC ECU.
Continuity
HINT: Resistance of the TRAC actuator solenoid is 2 

Repair or replace harness or connector.
Repair or replace harness or TRAC actuator.
Check continuity between terminal 3 of R/B No.5 (for TRAC solenoid relay) and
terminals (A22) 2 and (A22) 8 of ABS & TRAC ECU.
INSPECTION PROCEDURE
BR±78± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

Check TRAC solenoid relay.
Remove TRAC solenoid relay from R/B No. 5.
Check continuity between each terminal of TRAC
solenoid relay shown below.
Replace TRAC solenoid relay.
Terminals 1 and 3Open
Continuity
(Reference value 80 )Terminals 4 and 6
Terminals 2 and 3Continuity
1. Apply battery voltage between terminals
4 and 6.
2. Check continuity between terminal shown
below.
Repair or replace harness or connector.
Terminals 1 and 3
OpenTerminals 2 and 3
Continuity
Check for open and short in harness and connector between TRAC
solenoid relay and ABS & TRAC ECU (See page
IN±30).
 
 
If the same code is still output after the diagnostic trouble code is deleted, check the contact
condition of each connection.
If the connections are normal, the ECU may be defective.
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)BR±79

DTC 17 18 TRAC Motor Relay Circuit
CIRCUIT DESCRIPTION
This relay circuit supplies power to the TRAC pump motor. While the TRAC is activated, the ECU switches the
motor relay ON and operates the TRAC pump motor.
 DTC No. Diagnostic Trouble Code Detecting Condition Trouble area
 
 
 
 
 
17
 
 
 
 
 
Conditions (1) and (2) continue for 0.2 sec.
or more:
(1) TRAC motor relay terminal (TMR)
voltage: Battery positive voltage
(2) Voltage of ABS & TRAC ECU terminal
MTT: 0 V 
 
 
 
 

TRAC motor relay

Open or short in TRAC motor relay circuit

ECU
 
 
 
 
 
 
18
 
 
 
 
 
 
Conditions (1) and (2) continue for 2 sec. or
more:
(1) TRAC motor relay terminal (TMR)
voltage: 0 V
(2) Voltage of ABS & TRAC ECU terminal
MTT: Battery positive voltage 
 
 
 
 
 

TRAC motor relay

B+ short in TRAC motor relay circuit

ECU
Fail safe function: If trouble occurs in this relay circuit, the ECU cuts off current to the TRAC solenoid relay
and prohibits TRAC control.
BR±80± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

INSPECTION PROCEDURE
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)BR±81
Check voltage between terminal 1 of R/B No. 5 (for TRAC motor relay)
and body ground.
Remove TRAC motor relay from R/B No. 5.
Measure voltage between terminal 1 of R/B No. 5
(for TRAC motor relay) and body ground.
Voltage: 10 Ð 14 V.
Check and repair harness or connector.
Check continuity between terminal 2 of R/B No. 5 (for TRAC motor relay)
and terminal 2 of TRAC pump motor.
Repair or replace harness or TRAC pump
motor.
Check continuity between terminal 2 of R/B No. 5
(for TRAC motor relay ) and terminal 2 of TRAC
pump motor.
Continuity.
HINT: There is a resistance of 4 Ð 6  between ter±
minals 2 and 3 of TRAC pump motor.

Check TRAC motor relay.
Remove TRAC solenoid relay from R/B No. 5.
Check continuity between each terminal of TRAC
solenoid relay shown below.
Terminals 1 and 2
Open
Continuity
(Reference value 62)Terminals 3 and 4
Terminals 1 and 2
Continuity
1. Apply battery voltage between terminals
3 and 4.
2. Check continuity between terminal shown
below.
Replace TRAC solenoid relay.
Repair or replace harness or connector.
Check for open and short in harness and connector between TRAC motor
relay and ABS & TRAC ECU (See page
IN±30).
If the same code is still output after the diagnostic trouble code is deleted, check the contact
condition of each connection.
If the connections are normal, the ECU may be defective. BR±82
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

DTC 21 22 23 24 ABS Actuator Solenoid Circuit
CIRCUIT DESCRIPTION
This solenoid goes on when signals are received from the ECU and controls the fluid pressure acting on the
brake cylinders, thus controlling the braking force.
 DTC No. Diagnostic Trouble Code Detecting Condition Trouble area
 







21






 
Conditions (1) through (3) continue for 0.05
sec. or more:
(1) ABS solenoid relay terminal (SR)
voltage: Battery positive voltage
(2) Voltage of ABS (& TRAC) ECU terminal
AST: Battery positive voltage
(3) When power transistor of ECU is ON,
voltage of terminal SFR is 0 V or battery
positive voltage. 
 
 
 
 
 
 

ABS actuator

Open or short in SFR circuit.

ECU
 







22






 
Conditions (1) through (3) continue for 0.05
sec. or more:
(1) ABS solenoid relay terminal (SR)
voltage: Battery positive voltage
(2) Voltage of ABS (& TRAC) ECU terminal
AST: Battery positive voltage
(3) When power transistor of ECU is ON,
voltage of terminal SFL is 0 V or battery
positive voltage. 
 
 
 
 
 
 

ABS actuator

Open or short in SFL circuit.

ECU
 








23







 
Conditions (1) through (3) continue for 0.05
sec. or more:
(1) ABS solenoid relay terminal (SR)
voltage: Battery positive voltage
(2) Voltage of ABS (& TRAC) ECU terminal
AST: Battery positive voltage
(3) When power transistor of ECU is ON,
voltage of terminal SRR is 0 V or battery
positive voltage.
 
 
 
 
 
 
 
 

ABS actuator

Open or short in SRR circuit.

ECU
 







24






 
Conditions (1) through (3) continue for 0.05
sec. or more:
(1) ABS solenoid relay terminal (SR)
voltage: Battery positive voltage
(2) Voltage of ABS (& TRAC) ECU terminal
AST: Battery positive voltage
(3) When power transistor of ECU is ON,
voltage of terminal SRL is 0 V or battery
positive voltage. 
 
 
 
 
 
 

ABS actuator

Open or short in SRL circuit.

ECU
Fail safe function: If trouble occurs in the actuator solenoid circuit, the ECU cuts off current to the solenoid relay
and prohibits ABS control.
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)BR±83