Yamaha YP250A 1999 Supplementary Service Manual page 66

NOTE:
S If the inlet and outlet to connect with the HU are mistaken, when the HU operation test is performed which is
shown in [D-6], the brake lever enters down to full stroke without responding and will be pushed back slow-
ly without pulsation.
S If the connection of front and rear side is mistaken, and the HU operation test is performed which is shown
in [D-6], the HU operation of front and rear sides will be performed in reverse steps.
5) Solenoid connector terminal
S Check if the front and rear solenoid connector terminals (HU and wire harness sides) are reversed.
Front
Rear
6) HU
If the problem does not come under any phenomena from 1) to 5), the function failure of hydraulic unit
could be thought. Replace the hydraulic unit and execute the secure piping and wiring. Check with the
HU operation test as described in [D-6].
[C-5-12]Malfunction code "51" (Front wheel will not recover from the locking tendency even though
the signal is continuously sent from the ECU to release the hydraulic state (while the battery
voltage is low).)
1) Rotation of wheels
Refer to [C-5-10] Malfunction code "41"
2) Master cylinder and caliper
Refer to [C-5-10] Malfunction code "41"
3) Brake fluid
Refer to [C-5-10] Malfunction code "41"
4) Brake hose line
Refer to [C-5-10] Malfunction code "41"
5) Solenoid coupler terminal
Refer to [C-5-10] Malfunction code "41"
6) HU
Refer to [C-5-10] Malfunction code "41"
ANTI-LOCK BRAKE SYSTEM (ABS)
Terminal color
Solenoid side Wire harness side
Red, white
Red, green
WARNING
Rear wheel side inlet: Brake hose 1 from the
rear master cylinder
Rear wheel side outlet: Brake hose 2 from the
rear brake caliper
Red, white
Red, green
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CHAS