2001 TOYOTA SEQUOIA traction control

IN±44
± INTRODUCTIONTERMS
44 Author: Date:
2005 SEQUOIA (RM1146U) T/M
Transmission
TMCTOYOTA Motor Corporation
TMMKTOYOTA Motor Manufacturing Kentucky, Inc.
TRCTraction Control System
TURBOTurbocharge
TWCThree±Way Catalyst
U/DUnderdrive
U/SUndersize
VCVVacuum Control Valve
VENTVentilator
VIMVehicle Interface Module
VINVehicle Identification Number
VPSVariable Power Steering
VSCVehicle Skid Control
VSVVacuum Switching Valve
VTVVacuum Transmitting Valve
VVT±iVariable Valve Timing±intelligent
W/With
WGNWagon
W/HWire Harness
W/OWithout
1STFirst
2NDSecond
2WDTwo Wheel Drive Vehicle (4 x 2)
3RDThird
4THFourth
4WDFour Wheel Drive Vehicle (4 x 4)
4WSFour Wheel Steering System
5THFifth

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.

DIDM4±01
DI±916
± DIAGNOSTICSABS WITH EBD & BA & TRAC & VSC SYSTEM
111 0 Author: Date:
2005 SEQUOIA (RM1146U)
FAIL±SAFE CHART
1. FAIL SAFE OPERATION
If there is a problem with sensor signals or actuator systems, the skid control ECU prohibits power supply
to the ABS & VSC actuator and informs the ECM of VSC system failure.
The ABS & VSC actuator turns off each solenoid and the ECM shuts off VSC control (traction control signal)
from the skid control ECU accordingly, which turns out to be as if the ABS, VSC and TRAC systems were
not installed.
The ABS, VSC, and TRAC control will be prohibited, but EBD control continues as much as possible. If EBD
control is impossible, the brake warning light comes on to warn the driver (See page DI±910).
MalfunctionSymptom
ABS systemABS, BA, TRAC, and VSC control prohibited
BA systemABS, BA, TRAC, and VSC control prohibited
EBD systemABS & EBD control prohibited
TRAC systemTRAC and VSC control prohibited
VSC systemTRAC and VSC control prohibited
HINT:

A malfunction in either the ABS or BA system will result in an identical operation, with ABS, BA, TRAC,
and VSC system control prohibited.

If control is prohibited due to a malfunction during operation, control will be disabled gradually. This
is to avoid sudden vehicle instability.

05_SEQUOIA_U (L/O 0408)
vii
2005 SEQUOIA from Aug. '04 Prod. (OM34424U)
Spark ignition system of your
To y o t a
The spark ignition system in your Toyota meets all re-
quirements of the Canadian Interference±Causing Equip-
ment Standard.
Installation of a mobile
two±way radio system
As the installation of a mobile two±way radio system in
your vehicle could affect electronic systems such as
multiport fuel injection system/sequential multiport fuel
injection system, electronic throttle control system,
cruise control system, anti±lock brake system, traction
control system (two±wheel drive models)/active traction
control system (four±wheel drive models), vehicle stabil-
ity control system, rear height control air suspension
system, tire pressure warning system, SRS airbag sys-
tem and seat belt pretensioner system, be sure to
check with your Toyota dealer for precautionary mea-
sures or special instructions regarding installation.

05_SEQUOIA_U (L/O 0408)
5
2005 SEQUOIA from Aug. '04 Prod. (OM34424U)
18. Ashtray
19. Cigarette lighter
20. Traction control off switch
(ªTRAC OFFº switch)
21. Cruise control switch
22. Tire pressure warning system reset
switch
23. Audio remote control switches
24. Tilt steering lock release lever
25. Roll sensing of curtain shield airbags
off switch
26. Instrument panel light control knob

05_SEQUOIA_U (L/O 0408)
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2005 SEQUOIA from Aug. '04 Prod. (OM34424U)
or
Driver 's seat belt reminder light*
1
Discharge warning light*
1
Low fuel level warning light*
1
Brake system warning light*
1
Malfunction indicator lamp*
1
Anti±lock brake system warning light*
1
Automatic transmission fluid temperature
warning light (four±wheel drive models)*
1
SRS warning light*
1
Open door warning light*
1
Low windshield washer fluid level warning
light*
1
Front passenger 's seat belt reminder light*
1
Vehicle stability control system/traction control
system (two±wheel drive models) or active
traction control system (four±wheel drive
models) warning light
*
1
Low tire pressure warning light*
1
Engine oil replacement reminder light*
1
Indicator symbols on the instrument panel

05_SEQUOIA_U (L/O 0408)
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2005 SEQUOIA from Aug. '04 Prod. (OM34424U)
Automatic transmission indicator lights
Traction control system off indicator light
(two±wheel drive models)
Vehicle stability control system off indicator light
(four±wheel drive models) Slip indicator light
Headlight high beam indicator lightOverdrive±off indicator light
Turn signal indicator lights
Engine immobilizer/theft deterrent system
indicator light
Front passenger occupant classification
indicator light
Roll sensing of curtain shield airbags off
indicator light
Headlight low beam indicator light
Tail light indicator lightLow speed four±wheel drive indicator light*
2
High speed four±wheel drive indicator light*
2
Center differential lock indicator light*
2
(four±wheel drive models)

05_SEQUOIA_U (L/O 0408)
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2005 SEQUOIA from Aug. '04 Prod. (OM34424U)
(f) Low Fuel Level Warning Light
This light comes on when the fuel level
in the tank becomes nearly empty. Fill up
the tank as soon as possible.
On inclines or curves, due to the move-
ment of fuel in the tank, the low fuel level
warning light may come on earlier than
usual.
(g) ªABSº Warning Light
The light comes on when the ignition key
is turned to the ªONº position. If the anti±
lock brake system and the brake assist
system work properly, the light turns off
after a few seconds. Thereafter, if either
of the systems malfunctions, the light
comes on again.
When the ªABSº warning light is on (and
the brake system warning light is off), the
anti±lock brake system, the brake assist
system, the traction control system (two±
wheel drive vehicles), the active traction
control system (four±wheel drive vehicles)
and the vehicle stability control system do
not operate, but the brake system still
operates conventionally.When the ªABSº warning light is on (and
the brake system warning light is off), the
anti±lock brake system does not operate
so that the wheels could lock up during
a sudden braking or braking on slippery
road surfaces.
If either of the following conditions
occurs, this indicates a malfunction
somewhere in the components moni-
tored by the warning light system. Con-
tact your Toyota dealer as soon as
possible to service the vehicle.

The light does not come on when the
ignition key is turned to the ªONº posi-
tion, or remains on.

The light comes on while you are dri-
ving.
A warning light turning on briefly during
operation does not indicate a problem.
CAUTION
If the ªABSº warning light remains on
together with the brake system warn-
ing light, immediately stop your ve-
hicle at a safe place and contact your
Toyota dealer.
In this case, not only the anti±lock
brake system will fail but also the
vehicle will become extremely unsta-
ble during braking.
(h) ªVSC TRACº Warning Light
This light warns that there is a problem
somewhere in the vehicle stability control
system and traction control system (two±
wheel drive models) or active traction con-
trol system (four±wheel drive models).
The light will come on when the ignition
key is turned to ªONº and will go off after
a few seconds.
If the light comes on while driving, the
system does not work. However, as con-
ventional braking operates when applied,
there is no problem to continue your driv-
ing.