2001 TOYOTA SEQUOIA brake light

DIDLV±01
F17996
Front Speed SensorABS & VSC Actuator
(w/ Skid Control ECU)Level Warning Switch
Rear Speed Sensor Rear Speed Sensor Rotor
Front Speed
Sensor Rotor
Parking Brake SwitchStop Light Switch
Center Diff. Lock Switch *1
TRAC OFF Switch *2
Steering Angle Sensor
DLC3Brake Inhibit RelayTranslate ECU
VSC BuzzerBrake Booster
(Including Active Brake Booster
Solenoid, Delta S Sensor and Boost-
er Pedal Switch)
Master Cylinder
Pressure Sensor
Front Speed Sensor Rotor
Front Speed Sensor
Yaw Rate Sensor
(Including Deceleration Sensor)
ABS Warning Light
VSC TRAC Warning light
VSC OFF Indicator Light *
1
TRAC OFF Indicator Light *2
BRAKE Warning Light
SLIP Indicator Light
*1: Only for 4WD
*2: Only for 2WDCenter Diff. Lock
Position Switch
DI±892
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1086 Author: Date:
2005 SEQUOIA (RM1146U)
LOCATION

DIDLX±01
DI±894
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1088 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DESCRIPTION
1. SYSTEM DESCRIPTION
HINT:

The yaw rate sensor and deceleration sensor are combined and in a single unit. This unit communi-
cates with the skid control ECU through the CAN communication system.

No changes have been made to the communication method between the VSC system and ECM. How-
ever, the communication method between the Translate ECU and ECM has been changed from serial
to CAN communication.
(a) ABS
(Anti±lock Brake System)
The ABS helps prevent the wheels from locking when the brakes are applied firmly or when braking
on a slippery surface.
(b) EBD
(Electronic Brake force Distribution)
The EBD control utilizes ABS, realizing proper brake force distribution between front and rear wheels
in accordance with driving conditions.
In addition, during braking while cornering, it also controls the brake forces of the right and left wheels,
helping to maintain vehicle behavior.
(c) BA (Brake Assist)
The primary purpose of the brake assist system is to provide an auxiliary brake force to assist the driver
who cannot generate a large enough brake force during emergency braking, thus helping to maximize
the vehicle's braking performance.
(d) TRAC
(Traction Control)
The TRAC system helps prevent the drive wheels from slipping if the driver presses down on the accel-
erator pedal excessively when starting off or accelerating on a slippery surface.
(e) VSC
(Vehicle Stability Control)
The VSC system helps prevent the vehicle from slipping sideways as a result of strong front wheel skid
or strong rear wheel skid during cornering.
2. ABS with EBD & BA & TRAC & VSC OPERATION
(a) The skid control ECU calculates vehicle stability tendency based on signals from the speed sensor,
yaw rate (deceleration) sensor and steering angle sensor. In addition, it evaluates the results of the
calculations to determine whether any control actions (control of the engine output torque by electronic
throttle control and of the wheel brake pressure by the brake actuator) should be implemented.
(b) The SLIP indicator blinks and the VSC buzzer sounds to inform the driver that the VSC system is oper-
ating. The SLIP indicator also blinks when TRAC is operating, and the operation being performed is
displayed.
3. FAIL SAFE FUNCTION
(a) When a failure occurs in the ABS & BA & TRAC & VSC systems, the ABS and VSC warning lights come
on and ABS & BA & TRAC & VSC operations are prohibited. In addition to this, when there is a failure
that disables EBD operation, the brake warning light also comes on and EBD operation is prohibited.
(b) If some control is prohibited due to a malfunction during its operation, that control will be cut off gradual-
ly not to change the stability of the vehicle suddenly.

DI93A±03
Inspector 's
Name:
Customer 's Name
Date Vehicle
Brought InRegistration DateRegistration No.
Frame No.
Odometer Reading/ /
/ /
Date Problem First Occurred
Frequency Problem Occurs/ /
ContinuousIntermittent ( times a day)
Remains ONDoes not Light Up
DTC Check1st Time
2nd TimeNormal System Code
Trouble Code (Code )
Symptomskm
miles
Check ItemNormal
ABS does not operate.
ABS does not operate efficiently.
Does not Light Up
ABS & BA & TRAC & VSC Check Sheet
VSC does not operate. (Wheels sideslip when turning sharply.)
ABS Warning Light
Abnormal
Remains ON
Does not Light Up
Remains ONDoes not Light Up
Remains ONDoes not Light Up
Remains ONDoes not Light Up
TRAC OFF Indicator
Light Abnormal*1
SLIP Indicator
Light Abnormal VSC TRAC Warning
Light Abnormal
BRAKE Warning
Light Abnormal
Malfunction
Indicator Light
TRAC does not operate. (Wheels spin when starting off rapidly.)
Remains ON
Does not Light UpVSC OFF Indicator
Light Abnormal*2
BA does not operate
Normal System Code
Trouble Code (Code )
DI±896
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1090 Author: Date:
2005 SEQUOIA (RM1146U)
CUSTOMER PROBLEM ANALYSIS CHECK
*1: Only for 2WD
*2: Only for 4WD

F02135
Start Position
End PositionWithin ± 5° DI±900
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1094 Author: Date:
2005 SEQUOIA (RM1146U)
(b) Check the yaw rate and deceleration sensor.
Shift the shift lever to the D position and drive the vehicle
at a vehicle speed of approx. 3 mph (5 km/h), turn the
steering wheel either to the left or right for 90° or more,
and turn the vehicle through 180 degrees. Check that the
VSC buzzer sounds for 3 seconds upon start off.
Stop the vehicle and shift the shift lever to the P position,
and check that the VSC buzzer sounds again for 3 se-
conds.
HINT:

If the VSC buzzer sounds twice, the sensor check has
been completed normally.

If the VSC buzzer does not sound, check the VSC buzzer
circuit (See page DI±1052), then do the sensor check
again.

Drive the vehicle through 180°. At the end of the turn, the
direction of the vehicle should be within 180° ± 5° of its
start position.

Do not spin the wheels.

If the buzzer sounds after start off, then the deceleration
sensor check has passed its check. If the buzzer sounds
at the completion of a curve, then the yaw rate sensor
check has passed its check. The buzzer sound should be
heard twice during the sensor checks.
(c) Check the master cylinder pressure sensor.
(1) Turn the ignition switch to the ON position.
(2) Keep the vehicle in a stationary condition on a level
surface for 2 sec. or more.
(3) Keeping the vehicle in a stationary condition and
not pressing on the brake pedal for 1 sec. or more,
depress the brake pedal with 147 N (15 kgf, 33 lbf)
or more for 2 sec. or more.
NOTICE:
If zero point calibration has never been performed on a new
ECU, master cylinder pressure sensor check cannot be
completed correctly. Perform zero point calibration first
(See page DI±897).
HINT:
At this time, the buzzer sounds for 3 seconds.
(d) Check the speed sensor.
Drive the vehicle straight forward.
When driving the vehicle at the speed of 28 mph (45 km/h)
or higher for several seconds, check that the ABS warn-
ing light goes off.
HINT:
There is a possibility that the sensor check is not completed if
the vehicle has its wheels spun or its steering wheel turned dur-
ing this check.
(e) Stop the vehicle.

± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±903
1097 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:

If the VSC buzzer sounds twice, the sensor check has
been completed normally.

If the VSC buzzer does not sound, check the VSC buzzer
circuit (see page DI±1052), then do the sensor check
again.

Drive the vehicle through 180°. At the end of the turn its
check, the direction of the vehicle should be within 180°
± 5° of its start position.

Do not spin the wheels.

If the buzzer sounds after start off, then the deceleration
sensor check has passed its check. If the buzzer sounds
at the completion of a turn its check, then the yaw rate
sensor check has passed. The buzzer sound should be
heard during the sensor checks.
(c) Check the master cylinder pressure sensor.
(1) Turn the ignition switch to the ON position.
(2) Keep the vehicle in a stationary condition on a level
surface for 2 sec. or more.
(3) Keeping the vehicle in a stationary condition and
not pressing on the brake pedal for 1 sec. or more,
depress the brake pedal with 147 N (15 kgf, 33 lbf)
or more for 2 sec. or more on a new ECU.
NOTICE:
If zero point calibration has never been performed on a new
ECU, master cylinder pressure sensor check cannot be
completed correctly. Perform zero point calibration first
(See page DI±897).
HINT:
At this time, the buzzer sounds for 3 seconds.
(d) Check the speed sensor.
Drive the vehicle straight forward.
When driving the vehicle at the speed of 28 mph (45 km/h)
or higher for several seconds, check that the ABS warn-
ing light goes off.
HINT:
There is a case that the sensor check is not completed if the ve-
hicle has its wheels spun or its steering wheel turned during this
check.
(e) Stop the vehicle.
(f) Read the DTC by following the prompts on the tester
screen.
HINT:
Refer to the hand±held tester operator's manual for further de-
tails.

DI93F±04
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±905
1099 Author: Date:
2005 SEQUOIA (RM1146U)
PROBLEM SYMPTOMS TABLE
If a normal code is indicated during the DTC 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 troubleshooting page.
NOTICE:

When replacing the skid control ECU, sensor, etc., turn the ignition switch OFF.

When replacing the master cylinder pressure, yaw rate and deceleration sensors and/or the
ECU, make sure to perform master cylinder pressure, yaw rate, and deceleration sensors' zero
point calibration (See page DI±897).
SymptomSuspected AreaSee page
ABS does not operate
When the following 1. to 4. are all normal and the problem
is still occurring, replace the skid control ECU.
1. Check the DTC reconfirming that the normal code is
output.
2. IG power source circuit
3. Speed sensor circuit
4. Check the hydraulic circuit for leakage.
DI±911
DI±957
DI±925
DI±1059
ABS does not operate efficiently
When the following 1. to 4. are all normal and the problem
is still occurring, replace the skid control ECU.
1. Check the DTC reconfirming that the normal code is
output.
2. Speed sensor circuit
3. Stop light switch circuit
4. Check the hydraulic circuit for leakage.
DI±911
DI±925
DI±963
DI±1059
ABS warning light abnormal
1. ABS warning light circuit
2. Skid control ECUDI±1021 or
DI±1025
BRAKE warning light abnormal
1. BRAKE warning light circuit
2. Skid control ECU
3. Translate ECUDI±1033 or
DI±1038
DTC check cannot be done
When the following 1. to 3. are all normal and the problem
is still occurring, replace the skid control ECU.
1. ABS warning light circuit
2. Tc terminal circuit
3. VSC TRAC warning light circuit
DI±1021 or
DI±1025
DI±1055
DI±1027
DI±1031
Speed sensor signal check cannot be done1. Ts terminal circuit
2. Skid control ECUDI±1057
TRAC does not operate
Only when 1. to 4. are all normal and the problem is still
occurring, replace the skid control ECU.
1. Check the DTC, reconfirming that the normal code is
output.
2. IG power source circuit
3. Check the hydraulic circuit for leakage
4. Speed sensor circuit
DI±911
DI±957
DI±1059
DI±925
TRAC does not operate efficiently
Only when 1. to 3. are all normal and the problem is still
occurring, replace the skid control ECU.
1. Check the DTC, reconfirming that the normal code is
output.
2. Check the hydraulic circuit for leakage
3. Speed sensor circuit
DI±911
DI±1059
DI±925

DIDM0±01
F16974
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±907
1101 Author: Date:
2005 SEQUOIA (RM1146U)
TERMINALS OF ECU
1. Skid Control ECU:
Symbols (Terminal No.)Terminal Description
GND (1)Skid control ECU ground
CANL (2)Vehicle CAN communication line
VCP (3)Pedal stroke sensor (Delta S Sensor) line
CANH (6)Vehicle CAN communication line
E3 (8)Pedal stroke sensor (Delta S Sensor) ground
VYS (11)Yaw rate sensor power source
IG1 (13)IG1 power supply
PIM (14)Pedal stroke sensor (Delta S Sensor) line
D/G (15)Diagnosis tester communication line
+BM (16)Motor relay power supply
BST (17)Brake booster line
PSNC (18)Brake booster line
SS1 (19)Yaw rate sensor signal line
STS (20)Brake booster line
PSNO (21)Brake booster line
BZ (22)Buzzer output
SS2 (23)Yaw rate sensor signal line
GYAW (24)Yaw rate sensor ground
PMC2 (25)M/C pressure sensor 2 signal
VCM2 (26)M/C pressure sensor 2 power supply
E2 (27)M/C pressure sensor 2 ground
PMC (28)M/C pressure sensor 1 signal
E1 (29)M/C pressure sensor 1 ground
VCM (30)M/C pressure sensor 1 power supply
BSTP (31)Brake booster line
GND2 (32)Skid control ECU ground
FL+ (33)FL wheel speed signal line
FL± (34)FL wheel speed signal line
WA (35)ABS warning light output
RR± (36)RR wheel speed signal line
RR+ (37)RR wheel speed signal line
BSW (38)Brake inhibit signal line
STP (39)Stop light switch signal input

F19198
Skid Control ECU
(harness side connector) DI±908
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1102 Author: Date:
2005 SEQUOIA (RM1146U)Symbols (Terminal No.) Terminal Description
TS (40)Sensor check input
+BO (41)Steering angle sensor line
RL+ (42)RL wheel speed signal line
RL± (43)RL wheel speed signal line
VSCW (44)VSC OFF indicator output
FR± (45)FR wheel speed signal line
FR+ (46)FR wheel speed signal line
+BS (47)Solenoid relay power supply
2. Terminal Inspection
Disconnect the connector and measure the voltage on the wire harness side.
HINT:
Voltage can not be measured with the connector connected to the skid control ECU as the connector is water
resistance.
Symbols (Terminal No.)Wiring ColorTerminal DescriptionConditionSpecified Condition
+BM (16) ± GND1, 2 (1, 32)B±R ± W±BMotor relay power supplyIG switch ON10 to 14 V
GYAW (24) ± GND1, 2 (1, 32)G ± W±BYaw rate sensor groundAlwaysBelow 1 W
E3 (8) ± GND1, 2 (1, 32)L ± W±BM/C pressure sensor 3
groundAlwaysBelow 1 W
E2 (27) ± GND1, 2 (1, 32)W ± W±BM/C pressure sensor 2
groundAlwaysBelow 1 W
E1 (29) ± GND1, 2 (1, 32)W ± W±BM/C pressure sensor 1
groundAlwaysBelow 1 W
STP (39) ± GND1, 2 (1, 32)G±Y ± W±BStop light switch signal in-
putBrake pedal depressed8 to 14 V
STP (39) ± GND1, 2 (1, 32)G±Y ± W±BStop light switch signal in-
putBrake pedal releasedBelow 1.5 V
+BS (47) ± GND1, 2 (1, 32)B±R ± W±BSolenoid relay power sup-
plyIG switch ON10 to 14 V