Toyota 2001 CELICA, Wiring Diagram

Page: 134 / 231

2001 CELICA (EWD432U)
136
ABS
This system controls the respective brake fluid pressures acting on the brake cylinders of the right front wheel, the left front
wheel, the right rear wheel and the left rear wheel when the brakes are applied in a panic stop so that the wheels do not lock.
This results in improved directional stability and steerability during panic braking.
1. INPUT SIGNALS
(1) Speed sensor signal
The speed of the wheels is detected and input to TERMINALS FL+, FR+, RL+ and RR+ of the ABS ECU.
(2) Stop light SW signal
A signal is input to TERMINAL STP of the ABS ECU when the brake pedal depressed.
2. SYSTEM OPERATION
During sudden braking the ABS ECU which has signals input from each of the sensor, controls current to the solenoid inside
the actuator and causes the hydraulic pressure acting on each of the wheel cylinder escape to the reservoir. The pump
inside the actuator is also operating at this time and it returns the brake fluid from the reservoir to the master cylinder,
preventing locking of the vehicle wheels.
If the ECU judges that the hydraulic pressure acting on the wheel cylinder is insufficient, the current acting on the solenoid is
controlled and the hydraulic pressure is increased. Holding of the hydraulic pressure is also controlled by the ECU, by the
same method as above. By repeated pressure reduction, holding and increase are repeated to maintain vehicle stability and
to improve steerability during sudden braking.
A10 (A), A11 (B) ABS ECU
(Connect the ECU connector)
(B)21 − GROUND : Approx. 12 volts with the ignition SW at ON position
(B) 8 − GROUND : Approx. 12 volts with the ignition SW at ON position
(A) 5 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(A) 6 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(A)11 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(A)12 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(B) 2 − GROUND : Approx.
12
volts with the ignition SW at
ON
position and the ABS warning light goes off
(B) 1 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(B)15 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(B)14 − GROUND : Approx. 12 volts with the ignition SW at ON position and the ABS warning light goes off
(B)13 − GROUND : Approx. 12 volts with the ignition SW at ON position
(B) 5 − GROUND : Approx. 12 volts with the brake pedal depressed
(B)12, (B) 25 − GROUND : Always continuity
: PARTS LOCATION
Code See Page Code See Page Code See Page
A4 A
32 (1ZZ − FE)
A7
32 (1ZZ − FE) C12 A 36
34 (2ZZ − GE) 34 (2ZZ − GE) C13 B 36
A5 B
32 (1ZZ − FE) A10 A 36 D1 36
34 (2ZZ − GE) A11 B 36 J10 37
A6
32 (1ZZ − FE) A15 38 P3 37
34 (2ZZ − GE) A16 38 S8 37
: RELAY BLOCKS
Code See Page Relay Blocks (Relay Block Location)
1 26 Engine Room R/B No.1 (Engine Compartment Left)
SYSTEM OUTLINE
SERVICE HINTS