CONSTRUCTION DESCRIPTION
FOUR-WHEEL ANTI-LOCK BRAKE SYSTEM (4ABS)35B-9
STARTUP CHECK
.When the startup vehicle speed reaches approxi-
mately 10 km/h (6 mph), ABS-ECU performs the fol-
lowing checks.
1. Motor, solenoid valve check (Initial startup* only)
Turns ON the motor relay in ECU, and checks the
pump motor operation. At the same time,
ABS-ECU sequentially energizes each solenoid
valve in a very short period and checks the valve
operation.
NOTE: *: Initial startup indicates a first startup
after the system has started.
2. Wheel speed sensor check
ABS-ECU checks for any wheels that have not
received wheel speed sensor signal from the
startup.
CONSTANT CHECK
.ABS-ECU constantly checks the following items.
1. ABS-ECU
Performs self-diagnosis in ECU.
2. ECU power supply
Checks if ECU power supply voltage stays within
the operational range.
3. Wheel speed sensor
(1) Monitors the output voltage of the sensor
signal wiring harness and checks for abnormal
output voltage (open/short circuit).
(2) Checks for any wheels that do not send pulse
signal while the vehicle is in motion.
(3) Checks if wheel speed which is abnormally
higher or lower than the vehicle speed is input.
4. Pump motor, solenoid valve
Checks that the ABS-ECU output signal and the
operating conditions of the pump motor and
solenoid valve agree with each other.
CAN COMMUNICATION
ABS-ECU outputs the ABS warning light and the
EBD warning light
* illumination request signals to the
combination meter through CAN communication.
NOTE: *: The brake warning light is used as EBD
control warning light.
FAIL-SAFE FUNCTION
If any malfunction is detected by the self-diagnostic
function, ABS-ECU illuminates the ABS warning light
and brake warning light
*, and it disables ABS and
EBD control.
NOTE: *: The brake warning light is used as EBD
control warning light.
DTC
No.ItemCountermeasures for failure
EBD controlABS controlBrake
warning lightABS warning
light
C100AAbnormality in FL wheel speed
sensor circuitExecuted
(Prohibited
when two or
more wheels
are faulty.)ProhibitedExtinguished*2Illuminated*3
C1015Abnormality in FR wheel speed
sensor circuit
C1020Abnormality in RL wheel speed
sensor circuit
C102BAbnormality in RR wheel speed
sensor circuit
C1011Abnormality in FL wheel speed
sensor signalExecuted
(Prohibited
when two or
more wheels
are faulty.)ProhibitedExtinguished*2Illuminated*3
C101CAbnormality in FR wheel speed
sensor signal
C1027Abnormality in RL wheel speed
sensor signal
C1032Abnormality in RR wheel speed
sensor signal
