1991 LEXUS SC400 brake

TRAC PUMP AND ACCUMULATOR
TRAC PUMP AND ACCUMULATOR
REMOVAL AND INSTALLATION
BR0F9±03
Remove and install the part, as shown.
MAIN POINTS OF REMOVAL AND
INSTALLATION
1. DRAIN OUT HIGH PRESSURE FLUID
(a) Connect a vinyl tube 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
spray out with great force, so be careful.
2. DISCONNECT AND CONNECT BRAKE LINE Using SST, disconnect and connect the brake line from/to the
accumulator.
SST 09751±36011
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
3. BLEED BRAKE SYSTEM AND TRAC SYSTEM
(See page BR±8)
BR±162
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)
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TRAC PUMP AND ACCUMULATOR
DISASSEMBLY AND ASSEMBLY
BR0FA±03
Disassemble and assemble the parts, as shown.
MAIN POINT
DISPOSAL METHOD OF TRAC ACCUMULATOR
(a) Loosen the gas plug about 2 turns to a position where the gas
can leak out.
(b) After confirming that all the gas has been drained out remove
the gas plug and dispose of the accumulator.
HINT: If the gas does not leak out even after the gas plug has
been loosened 2 turns, repeat the operation, turning the gas
plug a half turn to the left or right.
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)BR±163
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TROUBLESHOOTING
How to proceed with troubleshooting
Perform troubleshooting in accordance with the procedure on the followin\
g page.

CUSTOMER PROBLEM ANALYSIS
Using the customer problem analysis check sheet for reference, ask the c\
ustomer in as much detail as
possible about the problem.
CHECK AND CLEAR THE DIAGNOSTIC TROUBLE CODES (PRECHECK)
If the TRAC indicator light lights up, and the TRAC control does not ope\
rate, the ECU stores diagnostic
trouble codes corresponding to the problem in memory.
Before confirming the trouble, first check the diagnostic trouble code for any\
malfunction codes stored in
memory. When there are malfunction codes, make a note of them, then clear them and proceed to ª 
Problem Symptom Confirmationº.
 PROBLEM SYMPTOM CONFIRMATION,  SYMPTOM SIMULATION
Confirm the problem symptoms. If the problem does not reoccur, simulate the problem by initially checking
the circuits indicated by the diagnostic trouble code in step , using ªProblem simulation methodº.
 DIAGNOSTIC TROUBLE CODE CHECK
Check the diagnostic trouble codes. If a malfunction code is output, proceed \
to ª  Diagnostic Trouble
Code Chartº.
If the normal code is output, proceed to ª  Problem Symptoms Chartº.
Be sure to proceed to ª  diagnostic Trouble Code Chartº after steps and  are completed.
If troubleshooting is attempted only by following the malfunction code sto\
red in the memory, errors could
be made in the diagnosis.
 DIAGNOSTIC TROUBLE CODE CHART
If a malfunction code is confirmed in the diagnostic trouble code check,\
proceed to the inspection proce-
dure indicated by the matrix chart for each diagnostic trouble code.
 PROBLEM SYMPTOMS CHART
If the normal code is confirmed in the diagnostic trouble code check, perf\
orm inspection in accordance with
the inspection order in the problem symptoms chart.
 CIRCUIT INSPECTION
Proceed with diagnosis of each circuit in accordance with the inspection\
order confirmed in  and .
Determine whether the cause of the problem is in the sensor, actuators, wire harness and connectors or
the ECU.
\b SENSOR CHECK
Use the ABS warning light to check if each of the signals from speed sensors is \
being input correctly to
the ECU. Instructions for this check are given in the circuit inspection\
.
[10] REPAIRS After the cause of the problem is located, perform repairs by following the i\
nspection and replacement pro-
cedures in this manual.
[11] CONFIRMATION TEST
After completing repairs, confirm not only that the malfunction is eliminated\
, but also conduct a test drive
to make sure the entire TRAC system is operating correctly. And also check the ABS is operating correctly.
BR±166
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)
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BR±168BR±170
BR±172 BR±228
BR±170
BR±172
BR±186 ~ BR±226 BR±170IN±22
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)BR±167
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CUSTOMER PROBLEM ANALYSIS CHECK SHEET
BR±168±
BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)
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MEMO±
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)BR±169
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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±225 ).
DIAGNOSTIC TROUBLE CODE CHECK
1. Turn the ignition switch ON.
2. Using SST, connect terminals Tc and E1 of DLC2 or DLC 1.
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 ( BR±226 orBR±225 ).
As an example, the blinking patterns for normal code and
codes 11 and 21 are shown on the left.
4. Codes are explained in the code table on the next page.
5. After completing the check, disconnect terminals Tc and
E1, and turn off the display.
If two or more malfunctions are indicated at the same time,
the lowest numbered diagnostic trouble code will be dis-
played 1st.
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 thetester screen.
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.
BR±170
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)
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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 DOME
fuse, but in this case, other memory systems will also be can-
celled out.
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BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)BR±171
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