2001 TOYOTA SEQUOIA Yaw rate sensor

DIDLU±01
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±891
1085 Author: Date:
2005 SEQUOIA (RM1146U)
ABS WITH EBD & BA & TRAC & VSC SYSTEM
PRECAUTION
NOTICE:
When disconnecting the battery terminal, initialize the following system after the terminal is recon-
nected.
System NameSee Page
Back Door Power Window Control SystemBE±77

When there is a malfunction in the contact point of the terminals or installation problems with
parts, removal and installation of the suspected problem parts may return the system to the
normal condition either completely or temporarily.

In order to determine the malfunctioning area, be sure to check the conditions at the time the
malfunction occurred, such as by DTC output and freeze frame data output, and record it before
disconnecting each connector or removing and installing parts.

Since the ABS with EBD & BA & TRAC & VSC systems may be influenced by a malfunction in
the other systems, be sure to check for DTCs in the other systems.

Be sure to remove and install the ABS & VSC actuator and each sensor with the IG switch OFF
unless specified in the inspection procedure.

When removing and installing the ABS & VSC actuator and each sensor, be sure to check that
the normal display is output in test mode inspection and in DTC output inspection after instal-
ling all the parts.

After replacing the yaw rate sensor and/or the ABS & VSC actuator assembly, make sure to per-
form yaw rate and deceleration sensors' zero point calibration
(See page DI±897).

The CAN communication system is used for data communication between the skid control ECU
(included in the actuator), the steering angle sensor, and the yaw rate sensor (the deceleration
sensor is included). If there is trouble in the CAN communication line, the DTC of the commu-
nication line is output.

If the DTC of the CAN communication line is output, repair the malfunction and troubleshoot
the ABS with EBD & BA & TRAC & VSC systems.

Since the CAN communication line has its own length and route, it can not be repaired tempo-
rarily with the bypass wire, etc.

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

DIDLW±01
F19153
Speed Sensor
(Each Wheel)
Stop Lamp Switch
Parking Brake Switch
Delta S Sensor
Yaw Rate
(Deceleration) SensorABS & VSC Actuator
Skid Control
ECUCombination
Meter
Translate
ECUSteering Angle
Sensor
4WD ECU
ECM
CAN Communication SystemAir Suspension ECU (*1): CAN1 Circuit
(*2): CAN2 Circuit
(*3): Vehicle CAN Circuit(*2)
(*3) (*1)
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±893
1087 Author: Date:
2005 SEQUOIA (RM1146U)
SYSTEM DIAGRAM

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.

DIDLY±01
F09750
DLC3
Ts
Tc
CG
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±897
1091 Author: Date:
2005 SEQUOIA (RM1146U)
CALIBRATION
1. ZERO POINT CALIBRATION OF MASTER CYLINDER
PRESSURE, YAW RATE AND DECELERATION SEN-
SORS
HINT:
When having replaced the master cylinder pressure, yaw rate
and deceleration sensors and/or the ECU, make sure to per-
form master cylinder pressure, yaw rate and deceleration sen-
sors' zero point calibration.
NOTICE:

While obtaining the zero point, do not vibrate the ve-
hicle by tilting, moving or shaking it and keep it in a
stationary condition. (Do not start the engine.)

Be sure to do this on a level surface (within an inclina-
tion of 1 degree).
(a) Perform master cylinder pressure, yaw rate and decelera-
tion sensors zero point calibration.
(1) Using SST, connect terminals Ts and CG of the
DLC3.
SST 09843±18040
(2) Shift the shift lever to the P position.
(3) Turn the ignition switch to the ON position.
(4) Keep the vehicle in a stationary condition on a level
surface for 4 sec. or more.
(5) Keep your foot off the brake pedal.
Do not leave 4WD vehicles in the L4 position.
(6) Press the center diff. lock (TRAC OFF) switch 3
times within 3 seconds.
(7) Check that the VSC buzzer sounds for 3 seconds.
HINT:

If the VSC buzzer does not sound, do the zero point cal-
ibration again and/or check the VSC buzzer circuit (See
page DI±1052).

If the VSC buzzer does not sound, check for yaw rate and
deceleration sensor failure (See page DI±911).
(8) Turn the ignition switch OFF.
(9) Disconnect terminals Ts and CG of the DLC3.
(b) Perform steering angle sensor zero point calibration.
This calibration is carried out automatically by following
procedures below:
(1) Make sure the system is not in sensor check mode.
(2) Calibrate the steering angle sensor by driving the
vehicle in a straight line at more than 7 MPH (12
km/h) for 5 seconds.

DIDLZ±01
F09750
DLC3Ts
CG
BR3904
0.13 sec. 0.13 sec.
ON
OFF
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±899
1093 Author: Date:
2005 SEQUOIA (RM1146U)
TEST MODE PROCEDURE
1. When not using the hand±held tester:
SENSOR CHECK (TEST MODE)
NOTICE:
When having replaced the master cylinder pressure, yaw
rate and deceleration sensors and/or the ECU, perform
zero point calibration of the master cylinder pressure, yaw
rate and deceleration sensors (See page DI±897).
HINT:
If the ignition switch is turned from the ON to the ACC or LOCK
position in test mode, test mode DTCs will be erased.
(a) Procedures for test mode:
(1) Turn the ignition switch OFF.
(2) Check that the shift lever is in the P position, and
turn the steering wheel to the neutral position.
(3) Using SST, connect terminals Ts and CG of the
DLC3.
SST 09843±18040
(4) Start the engine.
(5) Check that the ABS and VSC TRAC warning lights
blink.
HINT:
If the ABS and VSC TRAC warning lights do not blink, inspect
the ABS warning light circuit, VSC TRAC warning light circuit
and Ts terminal circuit.
(6) Keep the vehicle in a stationary condition on a level
surface for 4 sec. or more.
ABS warning light circuitDI±1021 or DI±1025
VSC TRAC warning light circuitDI±1027 or DI±1031
Ts terminal circuitDI±1057

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.

D05981
Hand±held
Tester
DLC3
BR3904
0.13 sec. 0.13 sec.
ON
OFF
F02135
Start Position
End PositionWithin ± 5° DI±902
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1096 Author: Date:
2005 SEQUOIA (RM1146U)
2. When using the hand±held tester:
SENSOR CHECK (TEST MODE)
NOTICE:
When having replaced the master cylinder pressure, yaw
rate and deceleration sensors and/or ECU, perform zero
point calibration of the master cylinder pressure, yaw rate
and deceleration sensors (See page DI±897). Make sure
that this operation is done before performing the following.
(a) Procedures for test mode:
(1) Connect the hand±held tester to the DLC3.
(2) Check that the shift lever is in the P position, and
turn the steering wheel to the neutral position.
(3) Start the engine.
(4) Select the SIGNAL CHECK on the hand±held tes-
ter.
(5) Check that the ABS warning light and VSC TRAC
warning light blink.
HINT:
If the ABS and VSC TRAC warning lights do not blink, inspect
the ABS warning light circuit, VSC TRAC warning light circuit
and Ts terminal circuit.
(6) Keep the vehicle in a stationary condition on a level
surface for 4 sec. or more.
ABS warning light circuitDI±1021 or DI±1025
VSC TRAC warning light circuitDI±1027 or DI±1031
Ts terminal circuitDI±1057
(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,
check that the VSC buzzer sounds again for 3 seconds.