1991 LEXUS SC300 code 32

SPEED SENSOR SIGNAL CHECK
1. Turn the ignition switch to OFF.
2. Using SST, connect terminals Ts and E1 of DLC1.SST 09843±18020
3. Start the engine.
4. Check that the ABS warning light blinks. HINT: If the ABS warning light does not blink, inspect the ABS
warning light circuit (see page BR±144).
5. Drive vehicle straight forward. HINT: Drive vehicle faster than 45 km/h (28 mph) for several
seconds.
6. Stop the vehicle.
7. Using SST, connect terminals Tc and E1 of DLC1.
SST 09843±18020
8. Read the number of blinks of the ABS warning light. HINT: See the list of diagnosis trouble codes shown on the
next page.
If every sensor is normal, a normal code is output (A cycle of
0.25 sec. on and 0.25 sec. OFF is repeated).
If 2 or more malfunction are indicated at the same time, the
lowest numbered code will be displayed 1st.
9. After performing the check, disconnect terminals Ts and E1,Tc and E1 of DLC1, and ignition switch turned off.
BR±80
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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ECU DATA MONITOR USING LEXUS HAND±HELD TESTER
1. Hook up the LEXUS hand±held tester to the DLC2.
2. Monitor the ECU data by following the prompts on the testerscreen.
HINT: LEXUS hand±held tester has a ªSnapshotº function
which records the monitored data.
Please refer to the LEXUS hand±held tester operator's
manual for further details.
Diagnostic Trouble Code of Speed Sensor Check Function
 Code No.\
\
Diagnosis Trouble Area 

71
\


\
Low output voltage of right front speed sensor
 



Right front speed sensor
 
71
\
\
Low output voltage of right front speed sensor
 
Sensor installation
 72\
\
Low output voltage of left front speed sensor 
Left front speed sensor
 72\
\
Low output voltage of left front speed sensor 
Sensor installation
 
73
\
\
Low output voltage of right rear speed sensor
 
Right rear speed sensor
 73\
\
Low output voltage of right rear speed sensor 
Sensor installation
 
74
\
\
Low output voltage of left rear speed sensor
 
Left rear speed sensor 74\
\
Low output voltage of left rear speed sensor 
Sensor installation 

75
\


\
Abnormal change in output voltage of right front speed
sensor 



Right front speed sensor rotor
 

76
\


\
Abnormal change in output voltage of left front speed
sensor 



Left front speed sensor rotor
 

77
\


\
Abnormal change in output voltage of right rear speed
sensor 



Right rear speed sensor rotor
 

78\


\
Abnormal change in output voltage of left rear speed
sensor 



Left rear speed sensor rotor
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±81
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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 page for
troubleshooting.
 Symptoms\
 \
Inspection Circuit See page
 


ABS does not oper-
ate.\
 
\

\

Only when 1.±4. are all normal and the problem is still occurring,
replace the ABS (& TRAC) ECU. 


BR±76
 


\
 
\

\

1. Check the diagnostic trouble code, reconfirming that the nor-
mal code is output. 

BR±122
BR±118
 \
 \
2. IG Power Source Circuit. BR±65 or 68 


\
 
\

\
3. Speed sensor circuit.
 


 




\
 
\


\

\

4. Check the ABS actuator with a checker.
If abnormal, check the hydraulic circuit for leakage (see page
BR±138). 




 


ABS does not oper-
ate efficiently.\
 
\

\

Only when 1.±4. are all normal and the problem is still occurring,
replace the ABS (& TRAC) ECU. 


BR±76
 


\
 
\

\

1. Check the diagnostic trouble code, reconfirming that the nor-
mal code is output. 


BR±118
BR±142
 \
 \
2. Speed sensor circuit. BR±65
or 68
 \
 \
3. Stop light switch circuit 
 




\
 
\


\

\

4. Check the ABS actuator with a checker.
If abnormal, check the hydraulic circuit for leakage (see page
BR±138). 




 


ABS warning light ab-
normal.\
 
\

\

1. ABS warning light circuit. 

BR±144
 \
 \
2. ABS (& TRAC) ECU. 
 




Diagnostic trouble
code check cannot
be performed.\
 
\


\

\

Only when 1. and 2. are all normal and the problem is still occur-
ring, replace the ABS (& TRAC) ECU. 




BR±144
 \
 \
1. ABS warning light circuit BR±148 


\
 
\

\
2. To terminal circuit.
 


 


Speed sensor signal
check cannot be per-
formed.\
 
\

\

1. Ts terminal circuit. 


BR±150
 


\
 
\

\
2. ABS (& TRAC) ECU.
 


BR±82±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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OKNG
OKNG
3Check ABS solenoid relay.
C
OK
P
C
OK
Remove solenoid relay from R/B No. 6.
Check continuity between each terminal of ABS sole-
noid relay shown below.
1. Apply battery voltage between terminals 4 and 6.
2. Check continuity between each terminal of ABS so-
lenoid relay shown below.
Replace ABS solenoid relay.
4Check for open and short in harness and connector between ABS solenoid r\
elay and ABS (&
TRAC) ECU (See page IN±33).
Repair or replace harness or connector.
If the same code is still output after the diagnostic trouble code is dele\
ted, check the contact condition
of each connection.
If the connections are normal, the ECU may be defective.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±97
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OKNG
OKNG
3Check ABS solenoid relay.
C
OK
P
OK
C
Remove solenoid relay from R/B No. 6
Check continuity between each pair of terminal of motor
relay shown below.
1. Apply battery voltage between terminals 3 and 4.
2. Check continuity between terminals shown below.
Replace ABS motor relay.
4Check for open and short in harness and connector between ABS motor relay and ABS (&
TRAC) ECU (See page IN±33).
Repair or replace harness or connector.
If the same code is still output after the diagnostic trouble code is dele\
ted, check the contact condition
of each connection.
If the connections are normal, the ECU may be defective.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±101
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OKNG
OKNG
3Check TRAC solenoid relay.
C
OK
P
OK
C
Remove solenoid relay from R/B NO. 6.
Check continuity between each terminal of TRAC sole-
noid relay shown below.
1. Apply battery voltage between terminals 4 and 6.
2. Check continuity between terminals shown below.
Replace TRAC solenoid relay.
4Check for open and short in harness and connector between TRAC solenoid relay\
and ABS &
TRAC ECU (See page IN±33).
Repair or replace harness or connector.
If the same code is still output after the diagnostic trouble code is dele\
ted, check the contact condition
of each connection.
If the connections are normal, the ECU may be defective.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±105
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OKNG
OKNG
3Check TRAC motor relay.
C
OK
P
OK
C
Remove motor relay from R/B No. 6.
Check continuity between each pair of terminal of motor
relay shown below.
1. Apply battery voltage between terminals 3 and 4.
2. Check continuity between terminals shown below.
Replace TRAC motor relay.
4Check for open and short in harness and connector between TRAC motor relay and ABS &
TRAC ECU (See page IN±33).
Repair or replace harness or connector.
If the same code is still output after the diagnostic trouble code is dele\
ted, check the contact condition
of each connection.
If the connections are normal, the ECU may be defective.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±109
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OKNG
OKNG
INSPECTION PROCEDURE
1Check ABS actuator solenoid.
C
OK
Hint
Hint
OK
C
Check continuity between terminal 4 and 1, 3, 4, 6 of the ABS actuator connector.
Continuity
Resistance of each solenoid coil is 1.2
.
Check continuity between terminal 2 and 1, 4, 5, 6 of the ABS actuator connector.
Continuity
Resistance of each solenoid coil is 1.2
.
Replace ABS actuator.
2Check for open and short in harness and connector between ABS (& TRAC) ECU \
and actuator
(See page IN±33).
Repair or replace harness or connector.
If the same code is still output after the diagnostic trouble code is dele\
ted, check the contact condition
of each connection.
If the connections are normal, the ECU may be defective.
BR±112±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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