BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEMBC–19
BC
4. FAIL SAFE FUNCTION
(a) When a failure occurs in the ABS with BA, TRC and
VSC systems, the ABS and VSC warning lights
illuminate, the slip indicator light comes on*1 or
remains off*2, and the operations of those systems
are prohibited. In addition to this, when a failure
which disables the EBD operation occurs, the brake
warning light comes on and its operation is
prohibited.
HINT:
*1: for 2WD
*2: for 4WD
(b) If control is prohibited due to a malfunction during
operation, control is disabled gradually to avoid
sudden vehicle instability.
5. INITIAL CHECK
(a) When the vehicle speed first reaches approximately
6 km/h (4 mph) or more after the ignition switch is
turned ON, each solenoid valve and the motor of the
ABS and TRACTION actuator are sequentially
activated to perform electrical checks. During the
initial check, the operating sound of the solenoid
valve and motor can be heard from the engine
compartment, but this does not indicate a
malfunction.
6. SERVICE MODE
(a) VSC operation can be disabled by operating the
intelligent tester.
HINT:
Refer to the intelligent tester operator's manual for
further details.
7. FUNCTION OF COMPONENTS
Components Functions
Speed Sensor
(Semiconductor Type)Detects the wheel speed and sends the signal to skid
control ECU
Skid Control ECU
(Housed in ABS and TRACTION Actuator)• Processes the signals from each sensor to control the
ABS, BA, TRC, and VSC
• Sends and receives control signals to and from the
ECM, yaw rate and deceleration sensor, steering
sensor, etc. via CAN communication.
ABS and TRACTION Actuator • Consists of the master cylinder cut solenoid valve,
holding solenoid valve, pressure reduction solenoid
valve, pump motor, and reservoir, and adjusts the brake
fluid pressure applied to each wheel cylinder
• Houses the skid control ECU
Solenoid Relay • Supplies power to each solenoid
• Housed in the skid control ECU
Motor Relay (VSC MTR Relay) • Supplies power to the pump motor
• Installed in engine room No. 1 relay block
Fail-safe Relay (VSC FAIL Relay) • Cuts off power to the motor when the pump motor circuit
malfunctions
• Installed in engine room No. 1 relay block
BC–20BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
BC
HINT:
*1: w/ Downhill assist control
*2: for 2WD w/ AUTO LSD
Steering Sensor • Detects the steering extent and direction and sends
signals to the skid control ECU via CAN communication
• Has a magnetic resistance element which detects the
rotation of the magnet housed in the detection gear in
order to detect the changes in magnetic resistance and
the steering amount and direction
Yaw Rate and Deceleration Sensor • Yaw rate sensor detects the vehicle's angular velocity
(yaw rate) in the vertical direction based on the extent
and direction of the deflection of the piezoelectric
ceramics
• Deceleration sensor measures the capacity of the
condenser that changes the distance between the
electrodes depending on G force, which occurs when
the vehicle is accelerated, and converts the measured
value into electrical signals
• Sends signals to the skid control ECU via CAN
communication
Master Cylinder Pressure Sensor • Detects the brake fluid pressure in the master cylinder
• Housed in the ABS and TRACTION actuator
ECM• Controls the engine output when TRC and VSC are
operating with the skid control ECU via CAN
communication
Downhill Assist Control switch*1 Allows the driver to turn downhill assist control ON and OFF
AUTO LSD switch*2 Allows the driver to turn AUTO LSD ON and OFF
Combination Meter ABS Warning Light • Illuminates to inform the driver that a malfunction in the
ABS has occurred
• Blinks to indicate DTCs that relate to the ABS
VSC Warning Light • Illuminates to inform the driver that a malfunction in the
VSC system has occurred
• Blinks to indicate DTCs that relate to the VSC
Brake Warning light • Illuminates to inform the driver that the parking brake is
ON when the system is normal, and when the brake
fluid has decreased
• Illuminates to inform the driver that a malfunction in the
EBD has occurred
Slip Indicator Light • Blinks to inform the driver that TRC, VSC, downhill
assist control and hill-start assist control are operating
• Illuminates to inform the driver that a malfunction has
occurred in the TRC or VSC system
AUTO LSD Indicator Light*2 Lights up to inform the driver when AUTO LSD operation is
possible
Downhill Assist Control Indicator
Light*1Lights up to inform the driver when downhill assist control
operation is possible
Skid Control Buzzer • Intermittently sounds to inform the driver that the VSC is
operating
• Housed in the combination meter Components Functions
BC–24BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
BC
CHECK FOR INTERMITTENT
PROBLEMS
1. CHECK FOR INTERMITTENT PROBLEMS
HINT:
A momentary interruption (open circuit) in the connectors
and/or wire harness between the sensors and ECUs can
be detected by using the ECU DATA LIST function of an
intelligent tester.
(a) Turn the ignition switch OFF and connect the
intelligent tester (with CAN VIM) to the DLC3.
(b) Turn the ignition switch ON.
(c) Follow the prompts on the intelligent tester to
display the DATA LIST and select areas where a
momentary interruption should be monitored.
HINT:
• A momentary interruption (open circuit) cannot
be detected for 3 seconds after the ignition
switch is turned ON (initial check).
• If the status remains on the ERROR display,
check for continuity between the ECU and the
sensors, or between ECUs.
• The ERROR display on the intelligent tester
remains on for 1 second after the harness signal
changes from a momentary interruption (open
circuit) to normal condition.
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Item (Display) Measurement Item /
Range (Display)Normal Condition Diagnostic Note
FR SPD OPN FR speed sensor open detection /
ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
FL SPD OPN FL speed sensor open detection /
ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
RR SPD OPN RR speed sensor open detection
/ ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
RL SPD OPN RL speed sensor open detection /
ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
EFI COM OPN EFI communication open
detection / ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEMBC–25
BC
(d) While observing the screen, gently jiggle the
connector or wire harness between the ECU and
sensors, or between ECUs.
OK:
ERROR display does not change.
HINT:
The connector and/or wire harness have a
momentary interruption (open circuit) if the display
changes. Repair or replace the connector and wire
harness if either of them is faulty.
YAW RATE OPN Yaw rate sensor open detection /
ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
DECELERAT OPN Deceleration sensor open
detection / ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
STEERING OPN Steering angle sensor open
detection / ERROR or NORMALERROR: Momentary interruption
NORMAL: Normal-
M/C OPN Master cylinder pressure sensor
open detection / ERROR or
NORMALERROR: Momentary interruption
NORMAL: Normal- Item (Display) Measurement Item /
Range (Display)Normal Condition Diagnostic Note
C122685
BC–26BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
BC
CALIBRATION
1. DESCRIPTION
(a) After replacing components relating to the VSC or
performing "Front wheel alignment adjustment",
clear and read the sensor calibration data.
(b) Follow the chart to perform calibration.
2. CLEAR ZERO POINT CALIBRATION DATA (When
Using Intelligent Tester)
(a) Clear the zero point calibration data.
(1) Connect the intelligent tester (with CAN VIM) to
the DLC3.
(2) Turn the ignition switch ON.
(3) Operate the intelligent tester to erase the codes
(select "Reset Memory").
HINT:
Refer to the intelligent tester operator's manual
for further details.
(4) Using the intelligent tester, perform the zero
point calibration of the yaw rate and deceleration
sensor.
CAUTION:
If the ignition switch is turned ON for more
than 15 seconds with the shift lever in the P
position after zero point of the yaw rate and
acceleration sensor has been cleared, only
the zero point of the yaw rate sensor will be
stored. If the vehicle is driven under this
condition, the skid control ECU will
recognize that zero point calibration of the
acceleration sensor is not completed and will
indicate that there is a malfunction in the
VSC system using the indicator light.
Replacing Parts / Operation Necessary Operation
Skid Control ECU Yaw rate and deceleration sensor zero point calibration.
Yaw Rate Sensor 1. Clearing zero point calibration data
2. Yaw rate and deceleration sensor zero point calibration
Front Wheel Alignment Adjustment 1. Clearing zero point calibration data
2. Yaw rate and deceleration sensor zero point calibration
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BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEMBC–27
BC
3. PREFORM ZERO POINT CALIBRATION OF YAW
RATE AND DECELERATION SENSOR (When Using
Intelligent Tester)
NOTICE:
• While obtaining the zero point, do not vibrate the
vehicle by tilting, moving or shaking it and keep it
stationary. (Do not start the engine.)
• Perform this on a level surface (with an inclination
of less than 1
).
(a) Procedures for Test Mode.
(1) Check that the shift lever is in the P position and
apply the parking brake.
NOTICE:
DTCs C1210/36 and C1336/39 will be
recorded if the shift lever is not the P
position (see page BC-88).
(2) Connect the intelligent tester (with CAN VIM) to
the DLC3.
(3) Turn the ignition switch ON.
(4) Set the intelligent tester to test mode (select
"Test Mode").
HINT:
Refer to the intelligent tester operator's manual
for further details.
(b) Obtain the zero point of the yaw rate and
deceleration sensor.
(1) Keep the vehicle stationary on a level surface for
2 seconds or more.
(2) Check that the VSC warning light blinks as
shown in the illustration.
HINT:
• If the VSC warning light does not blink,
perform the zero point calibration again.
• The zero point calibration is performed only
once after the system enters test mode.
• Calibration cannot be performed again until
the stored data is cleared once.
(3) Turn the ignition switch OFF.
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C108848E14
BC–28BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
BC
4. CLEAR ZERO POINT CALIBRATION DATA (When not
Using Intelligent Tester)
(a) Clear the zero point calibration data.
(1) Turn the ignition switch ON.
(2) The warning light and indicator light come on for
3 seconds to indicate that the initial check is
completed.
(3) Using SST, connect and disconnect terminals 12
(TS) and 4 (CG) of the DLC3 4 times or more
within 8 seconds.
SST 09843-18040
(4) Check that the VSC warning light comes on.
(5) Remove SST from the terminals of the DLC3.
(6) Using a check wire, perform the zero point
calibration of the yaw rate and deceleration
sensor.
CAUTION:
If the ignition switch is turned ON for more
than 15 seconds with the shift lever in the P
position after zero point of the yaw rate and
acceleration sensor has been cleared, only
the zero point of the yaw rate sensor will be
stored. If the vehicle is driven under this
condition, the skid control ECU will
recognize that zero point calibration of the
acceleration sensor is not completed and will
indicate that there is a malfunction in the
VSC system using the indicator light.
5. PERFORM ZERO POINT CALIBRATION OF YAW
RATE AND DECELERATION SENSOR (When not
Using Intelligent Tester)
NOTICE:
• While obtaining the zero point, do not vibrate the
vehicle by tilting, moving or shaking it and keep it
stationary. (Do not start the engine.)
• Perform this on a level surface (with an inclination
of less than 1
).
(a) Procedures for Test Mode.
(1) Turn the ignition switch OFF.
(2) Using SST, connect terminals 12 (TS) and 4
(CG) of the DLC3.
SST 09843-18040
(3) Check that the shift lever is in the P position and
apply the parking brake.
NOTICE:
DTCs C1210/36 and C1336/39 will be
recorded if the shift lever is not the P
position (see page BC-88).
(b) Obtain the zero point of the yaw rate and
deceleration sensor.
(1) Turn the ignition switch ON.
(2) Keep the vehicle stationary on a level surface for
2 seconds or more.
H100769E03
H100769E03
BC–30BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
BC
TEST MODE PROCEDURE
HINT:
• By switching the skid control ECU from normal mode to
test mode, abnormality detection sensitivity is enhanced
and troubleshooting can be conducted efficiently.
• Perform a sensor check in test mode after the speed
sensor or sensor rotor has been repaired or replaced.
• If the ignition switch is turned from ON to ACC or OFF
during test mode, DTCs related to the signal check
function will be erased.
• During test mode, the skid control ECU stores all DTCs
related to the signal check function, and the DTCs are
erased if normality is confirmed. Any remaining DTCs are
those indicating abnormalities that were found.
1. CHECK SENSOR SIGNAL BY TEST MODE (When
Using Intelligent Tester)
(a) Procedures for test mode:
(1) Turn the ignition switch OFF.
(2) Check that the steering wheel is in the centered
position.
(3) Check that the shift lever is in the P position and
apply the parking brake.
(4) Connect the intelligent tester (with CAN VIM) to
the DLC3.
(5) Turn the ignition switch ON.
(6) Turn the tester on.
(7) Set the intelligent tester to Test Mode (select
"Signal Check").
HINT:
Refer to the intelligent tester operator's manual
for further details.
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