1995 TOYOTA SUPRA battery

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

DTC 25 27 TRAC Actuator Solenoid Circuit
CIRCUIT DESCRIPTION
The TRAC actuator solenoid operates in accordance with signals from the ECU and raises the fluid pressure
in and releases it from the brake cylinders.
 DTC No. Diagnostic Trouble Code Detecting Condition Trouble area 
 
 
 
 
25
 
 
 
 
 
Conditions (1) and (2) continue for 0.05 sec.
or more:
(1) TRAC solenoid relay terminal (TSR)
voltage: Battery positive voltage
(2) Voltage oS & TRAC ECU terminal AB
SMC: 0 V
 
 
 
 
 

TRAC actuator

Open or short in SMC circuit

ECU
 
 
 
 
 
 
27
 
 
 
 
 
 
Conditions (1) and (2) continue for 0.05 sec.
or more:
(1) TRAC solenoid relay terminal (TSR)
voltage: Battery positive voltage
(2) Voltage of ABS & TRAC ECU terminal
SRC: 0V
 
 
 
 
 
 

TRAC actuator

Open or short in SRC circuit

ECU
Fail safe function: If trouble occurs in this solenoid circuit, the ECU cuts off current to the ABS and TRAC solenoid
relays and prohibits ABS and TRAC control.
BR±86± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

DTC 41 IG Power Source Circuit
CIRCUIT DESCRIPTION
This is the power source for the ECU, hence the CPU and the actuators.
 DTC No. Diagnostic Trouble Code Detecting Condition` Trouble area 
 
 
 
 
 
 
41
 
 
 
 
 
 
 
When either of the following (1) or (2) is
detected:
(1) Voltage at ECU terminal IG1 is less than
9.5 V for more than 10 sec. while vehicle
speed is 3 km/h (1.9 mph) or more.
(2) Voltage at ECU terminal IG1 is more than
17 V for more than 1.2 sec.
 
 
 
 
 
 
 

Battery

IC regulator

Open or short in power source circuit

ECU
Fail safe function: If trouble occurs in the power source circuit, the ECU cuts off current to the ABS solenoid relay
and prohibits ABS control.
BR±92± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

Check battery positive voltage.
Remove ABS (& TRAC) ECU with connectors still
connected.
1. Turn ignition switch ON.
2. Measure voltage between terminals IG1 and
GND of ABS (& TRAC) ECU connector.
Voltage: 10 Ð 14 V
Check and repair the charging system.
Voltage: 10 Ð 14 V
Check voltage between terminals IG1 and GND of ABS (& TRAC) ECU
connector.
Check and replace ABS (& TRAC) ECU.
INSPECTION PROCEDURE.
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)BR±93

Check continuity between terminal GND of ABS (& TRAC) ECU
connector and body ground.
Measure resistance between terminals GND of
ABS (& TRAC) ECU connector and body ground.
Resistance: 1
or less
Check for short in all the harness and
components connected to ECU±IG fuse
(See attached wiring diagram).
Repair or replace harness or connector.
Check ECU±IG fuse.
Check for open in harness and connector be-
tween ABS (& TRAC) ECU and battery (See page
IN±30).
Remove ECU±IG fuse from J/B No. 1.
Check continuity of ECU±IG fuse.
Continuity BR±94
± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

Check ABS warning light.
Disconnect the connectors from solenoid relay.
Check continuity between each terminal of ABS
solenoid relay shown below.
Replace bulb or combination meter assembly.
See Combination Meter Troubleshooting on page BE±43.
(1) Apply battery positive voltage between termi-
nals (A9) 1 and (A8) 3.
(2) Check continuity between each terminal of
ABS solenoid relay shown below.
Connect the
test lead to terminal (A9)4 and the
 lead to the terminal (A9)5. Check continuity be-
tween the terminals.
Continuity
If there is no continuity, connect the  test lead to
terminal (A9)4 and the
lead to terminal (A9)5.
Recheck continuity between terminals.
Terminals (A9) 5 and (A9) 6
Terminals (A9) 2 and (A9) 5
Open
Continuity
Continuity
Open
Terminals (A9) 1 and (A8) 3
Terminals (A9) 5 and (A9) 6
Terminals (A9) 2 and (A9) 5
Continuity
(Reference value 80
)
Replace ABS control relay.
Check ABS solenoid relay.
Repair or replace and check for open in harness and connector between DLC1 and ABS solenoid
relay and body ground (See page IN±30).Repair or replace and check for open in harness and connector between DLC1 and ABS solenoid
relay and body ground (See page IN±30).
INSPECTION PROCEDURE (w/o TRAC)
Perform troubleshooting in accordance with the chart below for each trouble symptom.
 


ABS warning light does not light up
 
 Go to step [1]
 


ABS warning light remains on 
 Go to step [3]
BR±108± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

Check ABS warning light.
Disconnect the connectors from R/B No.5.
Check continuity between each terminal of ABS
solenoid relay shown below.
Replace bulb or combination meter assembly.
1. Apply battery positive voltage between ter±
minals 4 and 6.
2. Check continuity between each terminal of
ABS solenoid relay shown below.
Terminals 2 and 3
Terminals 1 and 3
Open
Continuity
Continuity
Open
Terminals 4 and 6
Terminals 2 and 3
Terminals 1 and 3
Continuity
(Reference value 80
)
Replace ABS solenoid relay.
Check ABS solenoid relay.
Repair or replace and check for open in harness and connector between DLC1 and ABS solenoid
relay and body ground (See page IN±30).
Connect the
test lead to terminal 5 and the 
lead to the terminal 3. Check continuity between
the terminals.
Continuity
If there is no continuity, connect the  test lead to
terminal 5 and the
lead to terminal 3. Recheck
continuity between terminals.
See Combination Meter Troubleshooting on page BE±43.
INSPECTION PROCEDURE (w/ TRAC)
Troubleshoot in accordance with the chart below for each trouble symptom.
 ABS warning light does not light up Go to step [1]
 ABS warning light remains on Go to step [3]
BR±110± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

BR±134
BR±137
BR±137
BR±138
BR±138
BR±138
BR±138
BR±142
BR±145
BR±147
BR±149
BR±149
BR±152
BR±152
BR±155
BR±156
BR±157
Open or short in sub±throttle actuator circuit
Step motor does not move to a position decided by ECU
Sub±throttle valve does not move even when the sub±throttle
valve is controlled to fully open position by ECU
Right front wheel speed sensor signal malfunction
Left front wheel speed sensor signal malfunction
Right rear wheel speed sensor signal malfunction
Left rear wheel speed sensor signal malfunction
Low battery positive voltage or abnormally high battery
positive voltage
Malfunction in ABS or TRAC (BRAKE) control system
Open or short in NE signal circuit
Main throttle position sensor circuit malfunction
Open or short in main throttle position sensor circuit
Sub±throttle position sensor circuit malfunction
Open or short in sub±throttle position sensor circuit
Engine & ECT system malfunction
ECM communication circuit malfunction
ABS & TRAC ECU communication circuit malfunction
Malfunction in TRAC ECU
DiagnosisCodeTRAC Indicator Light
Blinking PatternSee page
DIAGNOSTIC TROUBLE CODE CHART
If a malfunction code is displayed during the diagnostic trouble code check, check the circuit listed for that code
in the table below and proceed to the relevant page.
HINT: If the TRAC indicator light lights up and the TRAC indicator light does not blink when the DTC is checked,
check the blinking pattern of the ABS warning light and troubleshoot the ABS system.
*
1: If a malfunction is detected in ABS the TRAC OFF indicator light lights up instead of the TRAC indicator
light.
*
2: The TRAC indicator light does not light up even if an error is detected
*3: If a malfunction is detected, the TRAC OFF indicator light lights up instead of the TRAC indicator light.
*4: Depending on the malfunction, the TRAC indicator light does not light up. BR±128
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)