2001 TOYOTA SEQUOIA VSC system

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.

DI939±04
Vehicle Brought to Workshop
Customer Problem Analysis
P. DI±896
Check and Clear DTC
P. DI±911Items inside
are titles of pages in this manual,
with the page number in the bottom portion. See
the pages for detailed explanations.
Problem Symptom ConfirmationSymptom Simulation
P. IN±24
Symptom
does not occur
Symptom
occurs
DTC Check
P. DI±911
Sensor CheckCircuit Inspection
DTC Chart
P. DI±921Trouble codeProblem Symptoms Table
P. DI±905
Check for Fluid Leakage
P. DI±1059
Identification of Problem
Normal system code
Repair
Confirmation Test
End
1
2
3
4
5
67
89
10
11Step 2, 5, 8, 9, 11:
P. DI±925 ± DI±1057
Diagnostic steps permitting use of the
hand±held tester.
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
DI±895
1089 Author: Date:
2005 SEQUOIA (RM1146U)
HOW TO PROCEED WITH TROUBLESHOOTING
Troubleshoot in accordance with the following procedures:

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

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.

DI±898
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
1092 Author: Date:
2005 SEQUOIA (RM1146U)
(3) Stop the vehicle. Use the hand±held tester to check
that the steering angle value on the DATA LIST in-
creases when the steering wheel is turned left, and
decreases when turned right.
(4) Turn the ignition switch OFF.
HINT:

If the steering angle reads 1,150 degrees when the steer-
ing wheel is in any position, the sensor has not been cali-
brated.

Carry out the calibration procedure again.

DTC C1362/36 will be output from the skid control ECU
if the skid control ECU is replaced with a new one and/or
sensor calibration is not performed.

DTC C1362/36 will be deleted when sensor calibration is
complete.

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