Yamaha YP250A 1999 Supplementary Service Manual page 62

[C-5-5] Malfunction code "21" (Solenoid circuit is disconnected or short-circuited.)
Check the following procedures.
1) Solenoid connector
S Check if the solenoid connector terminal is disconnected. (Refer to ABS CONNECTOR LOCATION
CHART)
2) HU solenoid
S Check the continuity of solenoid (front or rear wheel)
S Check the insulation condition of all solenoid terminals and negative (–) terminal of battery. ! [D-5]
3) ABS harness
S Check the continuity in the solenoid circuit (See the figure below).
Fail-safe
relay
ECU
S Check the insulation condition of battery's negative (–) terminal and solenoid circuit.
[C-5-6] Malfunction code "31" (Disconnection is detected between the system of fail-safe relay and
solenoid.)
Check the following procedures.
1) ABS motor fuse
S Check if the ABS motor fuse beside the battery is blown.
2) Solenoid connector
S Check if the solenoid connector located in the side cover at right hand comes off or whether there is insuf-
ficient connection. (Refer to ABS CONNECTOR LOCATION CHART)
3) ABS harness
S Check the continuity of white/brown leads between the ECU and fail-safe relay. (Refer to ABS CIRCUIT
DIAGRAM)
S ECU coupler terminal (white/brown) is disconnected.
S Check the continuity of red leads between 1 and 2 , 1 and 3 of solenoid circuit.
Fail-safe
relay
4) Fail-safe relay
S Check if the fail-safe relay operates correctly.
ANTI-LOCK BRAKE SYSTEM (ABS)
red
white
green
red
red
red
Front
solenoid
red
red
Rear
solenoid
Front
solenoid
Rear
solenoid
54
CHAS
1 – 2
1 – 3
Continuity
between: 4 – 7
5 – 6
! [D-5]
! [D-1]
! [D-2]