Yamaha YP250A 1999 Supplementary Service Manual page 61

4 Rear wheel sensor output drops
S Sensor signal output may drop due to failures on wheel and sensor housing. Check if there are loose-
ness, distortion or bending with the assembled condition of these components.
NOTE:
In the case of riding on the extremely uneven roads continuously, the ABS warning light may flash. If the
scooter runs more with the light flashing, the malfunction code "11" or "12" may be recorded depending on
the condition.
[C-5-3] Malfunction code "13" (front wheel) and "14" (rear wheel) (Error signal is detected from
either front wheel (13) or rear wheel(14).)
1) Installation of wheel sensors or sensor rotors may not be normal.
1 Installation of sensors
S Check if the wheel sensor is correctly installed with the housing.
S Check if there is a looseness between the housings and wheels.
2 Installation of sensor rotors.
S Check if the rotors are correctly pressed in the wheels.
S Check if foreign materials enter the rotor installing part.
2) Teeth face of sensor rotor may be defective.
S Check if there are flaws on the teeth face of rotors.
In this case, check also if there are any foreign materials.
3) Sensor output may be lower.
S Sensor signal outputs may drop due to failures on bearings, wheel axle, wheel and sensor housing of
front or rear wheel. Check if there are looseness, distortion or bending with the assembled condition of
these components.
[C-5-4] Malfunction code "15" (front wheel sensor) and "16" (rear wheel sensor) (No continuity in
sensor circuits)
Disconnection is detected in the front or rear wheel sensor circuit.
S Sensor connector of the front or rear wheel comes off.
S Sensor or leads of the front or rear wheel is disconnected.
S Disconnection of the ABS harness sensor circuit. ! (Refer to ABS CIRCUIT DIAGRAM)
S ECU connector terminal of the ABS harness comes off.
NOTE:
S There is a possibility that the both sensor lead connectors are disconnected on front and rear wheels.
Check it.
S If the scooter rides on with the malfunction code "15" and "16" displayed and the malfunction with either
front or rear wheel is identified, the malfunction code will be rewritten from "15" and "16" to "11" or "12".
ANTI-LOCK BRAKE SYSTEM (ABS)
53
CHAS
! [D-3, 4]
! [D-3, 4]
! [D-3, 4]
! [D-3, 4]
! [D-3, 4]
! [D-3, 4]
! [D-3, 4]
! [D-1]