1991 LEXUS SC400 brake

 



Symbols
(Terminals No.) 


STD Voltage (V)\
 
\

\

Condition
 LBL
(A25±6) ± GND
(A25±22) 10±14\
 \
IG switch ON
Fluid in M/C reservoir tank above MIN level.
 

STP
 

±
 

GND
 

Below 1.5\
 
\

\
Stop light switch OFF 


STP
(A25±10) 
± 


GND
(A25±22) 

8±14
\
 
\

\
Stop light switch ON
 D/G
(A25±20) ± GND
(A25±22) 10±14\
 \
IG switch ON, ABS warning light OFF
 

Tc
(A26±3)
 

±
 

GND
(A25±22)
 

10±14
\
 
\

\
IG switch ON
 

Ts
(A26±1) 

±
 

GND
(A25±22) 

10±14
\
 
\

\
IG switch ON
 P 
±
 GND 10±14\
 \
IG switch ON, Shift position in ªPº position P
(A26±10) ± GND
(A25±22) Below 1.5\
 \
IG switch ON, Other shift position in ªPº position 

N
 

±
 

GND
(A25±22)
 

10±14
\
 
\

\
IG switch ON, Shift position in ªNº position
 
N
(A26±5) ± (A25±22) Below 1.5\
 \
IG switch ON, Other shift position in ªNº position
 


FR+
(A24±17) 
± 


FR±
(A24±4) 

AC generation\
 
\

\

IG switch ON
Slowly turn right front wheel.
 


FL+
(A24±5) 
± 


FL±
(A24±18) 

AC generation\
 
\

\

IG switch ON
Slowly turn left front wheel.
 


RR+
(A25±14) 
± 


RR±
(A25±3) 


AC generation\
 
\

\

IG switch ON
Slowly turn right rear wheel.
 RL+
(A25±4) ± RL±
(A25±15) AC generation\
 \
IG switch ON
Slowly turn left rear wheel.
 

FRO
(A26±15) 

±
 

GND
(A25±22) 

Pulse generation
\
 
\

\
IG switch ON
Slowly turn right front wheel.
 

FLO
(A26±6) 

±
 

GND
(A25±22) 

Pulse generation
\
 
\

\
IG switch ON
Slowly turn left front wheel.
 


RRO
(A26±13) 

±
 


GND
(A25±22) 

Pulse generation
\
 
\

\

IG switch ON
Slowly turn right rear wheel.
 


RLO
(A26±4) 
± 


GND
(A25±22) 

Pulse generation\
 
\

\

IG switch ON
Slowly turn left rear wheel.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±61
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BR0EZ±03
ABS ACTUATOR
ABS ACTUATOR REMOVAL AND
INSTALLATION
Remove and install the parts, as shown.
BR±62
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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MAIN POINT OF REMOVAL AND
INSTALLATION
1. w/ TRAC:DRAIN OUT HIGH PRESSURE FLUID
(a) Connect a vinyl t ube to the TRAC actuator bleeder plug, then
loosen the bleeder plug.
(b) When the fluid has flowed out, tighten the bleeder plug. CAUTION: Since the fluid is under high pressure, it could
stray out with great force, so be careful.
2. DISCONNECT AND CONNECT BRAKE LINE w/ TRAC:
Using SST, disconnect and connect the brake lines from/to
the ABS actuator and TRAC actuator.
SST 09023±00100
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
w/o TRAC:
Using SST, disconnect and connect the brake lines from/to
the ABS actuator.
SST 09023±00100
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
3. w/ TRAC:
REMOVE AND INSTALL TRAC ACTUATOR
Loosen and tighten the 3 bolts.
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
HINT: When loosening or tightening TRAC actuator installa-
tion bolts, lift the actuator bracket up slightly from the body.
4. BLEED BRAKE SYSTEM
(See page BR±8)
5. w/ TRAC: BLEED TRAC SYSTEM
(See page BR±10)
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±63
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BR0F0±04
ABS ACTUATOR DISASSEMBLY AND
ASSEMBLY
Remove and install the parts, as shown.
COMPONENTS
BR±64±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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ABS ACTUATOR INSPECTION
BR0F1±03
HINT: Using the ABS actuator checker (SST), check the op-
eration of the actuator. If the actuator does not operate,
check the operation of sub±wire harness G according to
instructions on pages BR±97 and BR101. If the solenoid and/
or pump motor relay are abnormal, replace the relay and in-
spect the actuator operation again.
w/o TRAC:
1. INSPECT BATTERY POSITIVE VOLTAGE
Battery positive voltage:
10±14V
2. DISCONNECT CONNECTORS FROM ACTUATORDisconnect the 2 connectors from the actuator.
3. CONNECT ACTUATOR CHECKER (SST) TO ACTUATOR
(a) Connect the actuator checker (SST) to the actuator side wire harnesses via the sub±wire harnesses (SST), as shown.
SST 09990±00150, 09990±00210, 09990±00250 and09990±00280
(b) Connect the red cable of the checker to the battery positive (+) terminal and the black cable to negative (±) terminal.
Connect the black cable of the sub±wire harnesses to the
battery negative (±) terminal or body ground.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±65
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4. INSPECT BRAKE ACTUATOR OPERATION
(a) Start the engine, and run it at idle speed.
(b) Turn the MAIN selector switch of the actuator checker to theªFRONT RHº position.
(c) Push and hold in the SUB MOTOR switch for a few seconds.
(d) Depress the brake pedal and hold it until step (g) is completed.
(e) Push the MAIN push switch and check that the brake pedal can not be depressed.
NOTICE: Do not keep the MAIN push switch pushing more
than 10 seconds.
(f) Re le a se th e switch , an d ch e ck th a t th e p edal can be
depressed.
(g) Push and hold in the SUB MOTOR switch for a few seconds, and check that the pedal returns.
(h) Release the brake pedal.
(i) Push and hold in the SUB MOTOR switch for a few seconds.
(j) Depress the brake pedal and hold it for about 15 seconds. As
you hold the pedal down, push the SUB MOTOR switch for
a few seconds. Check that the brake pedal does not pulsate.
5. INSPECT FOR OTHER WHEELS
(a) Turn the MAIN selector switch to the ªFRONT LHº position.
(b) Repeat (c) to (j) of step 4, checking the actuator operation in the same way.
(c) Also, inspect the ªREARº positions following the same procedure.
BR±66
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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6. PUSH SUB MOTOR SWITCHPush and hold in the SUB MOTOR switch for a few seconds.
7. DISCONNECT ACTUATOR CHECKER (SST) FROM ACTUATOR
(a) Disconnect the actuator checker (SST) and sub±wire
harnesses (SST) from the actuator.
SST 09990±00150, 09990±00210, 09990±00250 and09990±00280
(b) Connect the actuator connectors.
(c) Clear the diagnostic trouble codes.
(See page BR±77)
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±67
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w/ TRAC:
1. INSPECT BATTERY POSITIVE VOLTAGE
Battery positive voltage:10±14 V
2. DISCONNECT CONNECTORS FROM ACTUATORDisconnect the 2 connectors from the actuator.
3. CONNECT ACTUATOR CHECKER (SST) TO ACTUATOR
(a) Connect the actuator checker (SST) to the actuator side wire harnesses via the sub±wire harnesses (SST), as shown.
SST 09990±00150 and 09990±00250
(b) Connect the red cable of the checker to the battery positive (+) terminal and the black cable to negative (±) terminal.
Connect the black cable of the sub±wire harnesses to the
battery negative (±) terminal or body ground.
(c) Place ªSHEET Aº (SST) on the actuator checker. SST 09990±00163
4. INSPECT BRAKE ACTUATOR OPERATION
(a) Start the engine, and run it at idle speed.
(b) Turn the selector switch of the actuator checker to the ªFRONT RHº position.
(c) Push and hold in the MOTOR switch for a few seconds.
(d) De p re ss th e bra ke p edal and hold it until step (g) is
completed.
BR±68
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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