Fail-Safe Relay; Composition And Operation - Yamaha 2003 FJR1300 Service Manual

ANTI-LOCK BRAKE SYSTEM (FJR1300A)

Composition and operation

The fail-safe relay is composed of the solenoid relay 1 and ABS motor relay 2. The solenoid relay
is activated (continuous) by signals transmitted from the ECU (ABS). As a result, the solenoid valve
3 can be operated.
If a malfunction occurs in the circuit, the solenoid relay is deactivated and it becomes impossible for
the solenoid valve to reduce the hydraulic pressure of the brake fluid and normal braking is
resumed.
The ABS motor relay is also activated by signals transmitted from the ECU (ABS) and operates
simultaneously when the ABS starts to reduce the hydraulic pressure of the brake fluid.
If the solenoid relay is turned off, the motor relay is also deactivated and the motor stops operating if
there is a malfunction.
1 Solenoid relay
2 ABS motor relay
3 Solenoid valve
4 Electric control unit (ECU)
5 Pump motor relay coil

• Fail-safe relay

The fail-safe relay controls the power supply of
the hydraulic unit and is located beside the
hydraulic unit.
1 Fail-safe relay
6 Pump motor monitor
7 ABS warning light
8 Fail-safe relay coil
9 Rear solenoid
0 Front solenoid
– 70 –
CHAS
A Power
B Fail-safe relay
C Hydraulic unit