2001 TOYOTA SEQUOIA ABS

D14171
Line Pressure
Control Pressure
Current Flow to Solenoid
D14172
ON
OFF
1 cycle
D14173
DI±656
± DIAGNOSTICSAUTOMATIC TRANSMISSION
850 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2714 Pressure Control Solenoid ºDº Performance
(Shift Solenoid Valve SLT)
SYSTEM DESCRIPTION
The linear solenoid valve (SLT) controls the transmission line
pressure for smooth transmission operation based on signals
from the throttle position sensor and the vehicle speed sensor.
The ECM adjusts the duty cycle of the SLT solenoid valve to
control hydraulic line pressure coming from the primary regula-
tor valve. Appropriate line pressure assures smooth shifting
with varying engine outputs.
(*): Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle.
For example, if A is the period of continuity in one cycle, and B
is the period of non±continuity, then
Duty Ratio = A/(A + B) x 100 (%)
DTC No.DTC Detection ConditionTrouble Area
P2714
ECM detects a malfunction on SLT (ON side) according to the
revolution difference of the turbine and the output shaft, and
also by the oil pressure. (2±trip detection logic)
Shift solenoid valve SLT remains open or closed

Valve body is blocked

Automatic transmission (clutch, brake or gear, etc.)
MONITOR DESCRIPTION
The ECM calculates the amount of heat absorbed by the friction material based on the difference in revolu-
tion (clutch slippage) between the turbine and output shaft. The ECM turns on the MIL and outputs this DTC
when the amount of heat absorption exceeds the specified value.
When the shift solenoid valve SLT remains on, oil pressure goes down and clutch engagement force de-
creases.
NOTE: If you continue driving under these conditions, the clutch will burn out and the vehicle will no longer
be drivable.
DIDJL±01

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.

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.