1995 TOYOTA SUPRA brake light

Ts Terminal Circuit
CIRCUIT DESCRIPTION
The sensor check circuit detects abnormalities in the speed sensor signal which cannot be detected with the
diagnostic trouble code check.
Connecting terminals Ts and E1 of the DLC1 in the engine compartment starts the check.
Check for open and short in harness and connector between ABS (&TRAC)
ECU and DLC1, DLC1 and body ground (See page IN±30).
Turn ignition switch ON.
Measure voltage between terminals Ts and E1 of
DLC1.
Voltage: 10 ± 14 V
If ABS warning light does not blink even
after Ts and E1 are connected, the ECU may
be defective.
Repair or replace harness or connector.
Check and replace ABS (& TRAC) ECU.
INSPECTION PROCEDURE.
BR±114± BRAKE SYSTEMANTI±LOCK BRAKE SYSTEM (ABS)

CUSTOMER PROBLEM ANALYSIS CHECK SHEET
 
 TRAC Check Sheet
Inspector 's
Name:
   Registration No. 
 
 Customer 's Name
 
 
 
 Registration Year
 
 //
 
 
 
 
 
 Frame No. 
 
 
 
Date Vehicle
Brought In 
 // 
 Odometer Reading 
 
km
Miles
 
 
 
Date Problem First Occurred
 
 
 
//
 
  Frequency Problem Occurs 
  Continuous  Intermittent ( Times a day)

 
 
 
 TRAC does not operate. (Wheels spin when starting rapidly).
 
 
  Symptoms
 
 
 
TRAC Indicator
Light Abnormal
 
 
 Remains ON Blinks Does not Light Up
 
 
 
 
 
 
TRAC OFF Indicator
Light Abnormal
 
 
 
Remains ON Does not Light Up
 
 
Ch k It
 
 ABS Warning LIght 
 Normal Malfunction Code (Code )
 
 
Check Item 
 
Malfunction
Indicator Lamp 
 NormalMalfunction Code (Code )
 
 Diagnostic
Tro ble Code
 
 1st Time
 
 Normal CodeMalfunction Code (Code )
 
 
 
Trouble Code
Check 
 
 
2nd Time
 
 
 
Normal CodeMalfunction Code (Code )
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±125

DIAGNOSIS SYSTEM
INDICATOR CHECK
When the ignition switch is turned ON, check that the TRAC
indicator light goes on for 3 seconds.
HINT: If the indicator check result is not normal, proceed to
troubleshooting for the TRAC indicator light circuit (See page
BR±162).
DIAGNOSTIC TROUBLE CODE CHECK
1. Turn the ignition switch ON.
2. Using SST connect terminals Tc and E1 of DLC2 or DLC1.
SST 09843±18020
3. Read the diagnostic trouble code from the TRAC indicator
light on the combination meter.
HINT: If no code appears, inspect the diagnostic circuit or
TRAC indicator light circuit (See page BR±162 or BR±163)
As an example, the blinking patterns for normal code and
code 32 are shown on the left.
4. Codes are explained in the code table on page BR±128.
5. After completing the check, disconnect terminals Tc and E1,
and turn off the display.
If 2 or more malfunctions are indicated at the same time, the
lowest numbered diagnostic trouble code will be displayed
first.
ECU DATA MONITOR USING TOYOTA
HAND±HELD TESTER
1. Hook up the TOYOTA hand±held tester to the DLC2
2. Monitor the ECU data by following the prompts on the tester
screen.
HINT: TOYOTA hand±held tester has a ºSnapshotº function
which records the monitored data.
Please refer to the TOYOTA hand±held tester operator's
manual for further details. BR±126
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)

DIAGNOSTIC TROUBLE CODE
CLEARANCE
1. Using SST, connect terminals Tc and E1 of DLC2 or DLC1.
SST 09843±18020
2. IG switch ON.
3. Clear the diagnostic trouble codes stored in ECU by
depressing the brake pedal 8 or more times within 3 seconds.
4. Check that the TRAC indicator light shows the normal code.
5. Remove the SST from the terminals of DLC2 or DLC1.
HINT: Cancellation can also be done by removing the ECU±B
fuse, but in this case, other memory systems will also be can-
celled out.
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±127

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)

ECU TERMINALS STANDARD VALUE
ABS & TRAC ECU:
ConditionSTD Voltage (V)Symbols
(Terminals No.)
Always
IG switch ON
IG switch ON, ABS warning light OFF
IG switch ON
IG switch ON, TRAC and TRAC OFF indicator light OFF
IG switch ON
IG switch ON, ABS warning light OFF
IG switch ON, ABS warning light OFF
IG switch ON, ABS warning light OFF
IG switch ON, ABS warning light OFF
IG switch ON, ABS warning light OFF
IG switch ON, TRAC and TRAC OFF indicator light OFF
IG switch ON, TRAC and TRAC OFF indicator light OFF
IG switch ON, ABS warning light ON
IG switch ON, ABS warning light OFF
IG switch ON, PKB switch ON
Fluid in M/C reservoir above MIN level.
IG switch ON, PKB switch OFF
Fluid in M/C reservoir above MIN level.
IG switch ON
Fluid in M/C reservoir above MIN level.
Stop light switch OFF
Stop light switch ON
IG switch ON, ABS warning light OFF
BR±130± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)

TRAC ECU:
ConditionSTD Voltage (V)Symbols
(Terminals No.)
Always
Always
IG switch ON
5 seconds after IG switch ON
Sub throttle valve fully open
5 seconds after IG switch ON
Sub throttle valve fully open
5 seconds after IG switch ON
Sub throttle valve fully open
5 seconds after IG switch ON
Sub throttle valve fully open
5 seconds after IG switch ON
Sub throttle valve fully open
5 seconds after IG switch ON
Sub throttle valve fully open
Engine idling, Main throttle valve fully closed
Engine idling, Main throttle valve fully open
IG switch ON, Sub throttle valve fully closed
IG switch ON, Sub throttle valve fully open
Idling
IG switch ON, TRAC cut switch pushed in
IG switch ON, TRAC cut switch released
IG switch ON, PKB switch ON
Fluid in M/C reservoir above MIN level
IG switch ON, PKB switch OFF
Fluid in M/C reservoir above MIN level
IG switch ON, TRAC indicator light ON
IG switch ON, TRAC OFF indicator light ON
IG switch ON, TRAC OFF indicator light OFF
Stop light switch OFF
Stop light switch ON
IG switch ON
IG switch ON
Slowly turn right front wheel
IG switch ON
Slowly turn left front wheel
IG switch ON
Slowly turn right rear wheel
IG switch ON
Slowly turn left rear wheel
Below 1.0
Below 1.0
Pulse generation
Below 1.5
Below 1.5
Below 2.0
Below 1.5
Pulse generation
Pulse generation
Pulse generation
Pulse generation
BR±132± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)

PROBLEM SYMPTOMS CHART
If a normal code is displayed during the diagnostic trouble code check but the problem still occurs, check the
circuits for each problem symptom in the order given in the table below and proceed to the relevant troubleshoot-
ing page.
 
 Symptoms
 
 Inspection Circuit
 
 See page
 
 
 
 
 
 
 
 
TRAC does not
operate.
 
 
 
 
 
 
 
 
Only when 1. ~ 5, are all normal and the problem is still occurring,
replace the TRAC ECU.
1. Check the diagnostic trouble code, reconfirming that the Normal
code is output
2. IG power source circuit.
3. Check the hydraulic circuit for leakage.
4. Speed sensor circuit.
5. Park/neutral position switch circuit. 
 
 
 
 
 
 
 
BR±126
BR±142
BR±165
BR±138
AT1±81 or AT2±101
 
 TRAC indicator light
abnormal. 
 1. TRAC indicator light circuit.
2. TRAC ECU. 
 BR±162
 
 
 
 
 
TRAC OFF indicator
light abnormal.
 
 
 
 
 
Only when 1. and 2. are all normal and the problem is still occurring,
replace the TRAC ECU.
1. TRAC OFF indicator light circuit.
2. TRAC cut switch circuit.
 
 
 
 
 
BR±159
BR±159
 
 
 
 
Diagnostic trouble
code check cannot
be performed.
 
 
 
 
Only when 1. and 2, are all normal and the problem is still occurring,
replace the TRAC ECU.
1. TRAC indicator light circuit
2. Tc terminal circuit. 
 
 
 
BR±162
BR±163
± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)BR±133