2006 TOYOTA RAV4 4wd

BC–10BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
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(1) Operation description:
The skid control ECU detects the vehicle's slip
condition by receiving signals from each speed
sensor and the ECM via CAN communication.
The skid control ECU controls engine torque
with the ECM via CAN communication and
brake fluid pressure through the pump and
solenoid valve. The slip indicator light blinks
when the system is operating.
for 4WD: The VSC warning light comes on when
the TRC system malfunctions.
for 2WD: The VSC warning light and SLIP
indicator light comes on when the TRC system
malfunctions.

BC–12BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
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(1) Operation description:
The skid control ECU determines the vehicle
condition by receiving signals from the speed
sensor, the yaw rate and deceleration sensor
and the steering sensor. The skid control ECU
controls engine torque with the ECM via CAN
communication and brake fluid pressure through
the pump and solenoid valve. The slip indicator
light blinks and the skid control buzzer sounds
when the system is operating.
for 4WD: The VSC warning light comes on when
the TRC system malfunctions.
for 2WD: The VSC warning light and slip
indicator light come on when the TRC system
malfunctions.
(f) Downhill Assist Control:
When the downhill assist control switch is pressed
with the shift lever on L or R range and the
accelerator and brake pedals not depressed,
downhill assist control is activated. When activated,
4-wheel hydraulic pressure control occurs in order
to maintain a constant low vehicle speed without
causing the wheels to become locked. Thus, the
vehicle can descend a steep hill in a stable manner.
HINT:
• Depressing the accelerator and brake pedal
cancels control of the downhill assist control.
• Downhill assist control begins operating when
driving down on a slope at a speed of 25 km/h
(16 mph) or less with the engine brake applied.

BC–18BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
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(3) Front Wheel Skid Tendency
When the skid control ECU determines that
there is a front wheel skid tendency, it controls
the VSC to dampen the front wheel skid. At the
same time, it effects cooperative control with the
EPS to provide steering torque assist, which
facilitates the driver's steering maneuvers to
stabilize the vehicle posture. To prevent
excessive steering maneuvers, it provides a
steering torque assist. This assist increases the
resistance to counter the driver's steering effort,
if the driver turns the steering wheel excessively.
(4) Rear Wheel Skid Tendency
When the skid control ECU determines that
there is a rear wheel skid tendency, it controls
the VSC to dampen the rear wheel skid. At the
same time, it effects cooperative control with the
EPS to provide steering torque assist, which
facilitates the driver's steering maneuvers in the
direction to correct the rear wheel skid.
(5) Acceleration During Cornering
A sudden acceleration of the vehicle during
cornering may cause a drive wheel to freewheel,
which could cause the front wheels or rear
wheels to skid. If the skid control ECU
determines that there is freewheeling of a drive
wheel, a front wheel skid tendency, or a rear
wheel skid tendency, it effects cooperative
control with the 4WD system to optimally control
the drive torque distribution to the front and rear
wheels. Furthermore, it controls the TRC and
the VSC as needed to ensure driving stability
and acceleration performance.
(b) Operation
The operation of the solenoid valves under the
cooperative control is the same as the TRC or VSC
operation.
3. ABS WITH EBD, BA, TRC AND VSC OPERATION
(a) The skid control ECU calculates vehicle stability
tendency based on the signals from the 4 wheel
speed sensors, the yaw rate and deceleration
sensor and the steering 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 brake fluid pressure by the ABS
and TRACTION actuator) should be implemented.
(b) The slip indicator blinks and the skid control buzzer
sounds to inform the driver that the VSC system is
operating. The slip indicator also blinks when
traction control is operating, and the operation being
performed is displayed.

BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEMBC–19
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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–40BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
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• If all sensors are normal, a normal system
code is output (the light comes on for 0.25
seconds at intervals of 0.25 seconds).
(4) After the check, disconnect SST from terminals
13 (TC) and 4 (CG) of the DLC3.
(5) Turn the ignition switch OFF.
3. DTC OF TEST MODE FUNCTION (SIGNAL CHECK)
DTC of ABS sensor check function:
DTC of VSC sensor check function:
HINT:
• *: w/ Downhill assist control
• The DTCs in this table are only output in Test Mode.
• The detection of DTCs from C1271/71 to C1274/74 is
completed before the vehicle speed reaches 5 km/h
(3 mph).
• The detection of DTCs from C1275/75 to C1278/78 is
completed before the vehicle speed reaches 45 km/h
(28 mph).
DTC No. Diagnosis Trouble Areas
C1271/71 Low output signal of front speed sensor RH • Front speed sensor RH
• Speed sensor circuit
• Sensor installation
C1272/72 Low output signal of front speed sensor LH • Front speed sensor LH
• Speed sensor circuit
• Sensor installation
C1273/73 Low output signal of rear speed sensor RH • Rear speed sensor RH (for 4WD)
• Skid control sensor RH (for 2WD)
• Speed sensor circuit
• Sensor installation
C1274/74 Low output signal of rear speed sensor LH • Rear speed sensor LH (4WD)
• Skid control sensor LH (2WD)
• Speed sensor circuit
• Sensor installation
C1275/75 Abnormal change in output signal of front
speed sensor RH• Sensor installation
• Speed sensor rotor
• Foreign matter on sensor tip or sensor
rotor
C1276/76 Abnormal change in output signal of front
speed sensor LH• Sensor installation
• Speed sensor rotor
• Foreign matter on sensor tip or sensor
rotor
C1277/77 Abnormal change in output signal of rear
speed sensor RH• Sensor installation
• Speed sensor rotor
• Foreign matter on sensor tip or sensor
rotor
C1278/78 Abnormal change in output signal of rear
speed sensor LH• Sensor installation
• Speed sensor rotor
• Foreign matter on sensor tip or sensor
rotor
C1279/79 Deceleration sensor output voltage
malfunction• Yaw rate sensor
• Sensor installation
C1281/81 Master cylinder pressure sensor output
malfunction• Master cylinder pressure sensor
• Brake pedal load sensing switch (w/ 16-
inch disc)
DTC No. Diagnosis Trouble Areas
C0371/71 Yaw rate sensor Yaw rate sensor
C1379/74* Downhill assist control operation switch Downhill assist control switch