CHAS
FOREWORD
This Supplementary Service Manual has been prepared to introduce new service and data for the YP250A
’99. For complete service information procedures it is necessary to use this Supplementary Service Manual
together with the following manual.
YP250 SERVICE MANUAL: 4UC-AE1
YP250 (J) SUPPLEMENTARY SERVICE MANUAL: 4UC-AE2
YP250D SUPPLEMENTARY SERVICE MANUAL: 5DF-AE1
YP250A ’99
SUPPLEMENTARY
SERVICE MANUAL
1998 by Yamaha Motor Co., Ltd.
First Edition, July 1998
Any reproduction or unauthorized use
without the written permission of
Yamaha Motor Co., Ltd.
is expressly prohibited.
EB001000
NOTICE
This manual was produced by the Yamaha Motor Company primarily for use by Yamaha dealers and their
qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual, so it is
assumed that anyone who uses this book to perform maintenance and repairs on Yamaha scooter has a
basic understanding of the mechanical ideas and the procedures of scooter repair. Repairs attempted by
anyone without this knowledge are likely to render the scooter unsafe and unfit for use.
Yamaha Motor Company, Ltd. is continually striving to improve all its models. Modifications and significant
changes in specifications or procedures will be forwarded to all authorized Yamaha dealers and will appear
in future editions of this manual where applicable.
NOTE:
Designs and specifications are subject to change without notice.
IMPORTANT INFORMATION
Particularly important information is distinguished in this manual by the following notations.
The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY
IS INVOLVED!
WARNING
CAUTION:
NOTE:
Failure to follow WARNING instructions could result in severe injury or death to the
scooter operator, a bystander or a person inspecting or repairing the scooter.
A CAUTION indicates special precautions that must be taken to avoid damage to
the scooter.
A NOTE provides key information to make procedures easier or clearer.
YP002000
HOW TO USE THIS MANUAL
MANUAL ORGANIZATION
This manual consists of chapters for the main categories of subjects. (See “Illustrated symbols”)
1st title 1 :
This is the title of the chapter with its symbol on the upper right corner of each page.
2nd title 2 :
This title indicates the section of the chapter and only appears on the first page of each section. It is located in the upper left corner of the page.
3rd title 3 :
This title indicates a sub-section that is followed by step-by-step procedures accompanied
by corresponding illustrations.
EXPLODED DIAGRAMS
To heps identify parts and clarify procedure steps, there are exploded diagrams at start of each removal and
disassembly section.
1. An easy-to-see exploded diagram 4 is provided for disassembly and assembly jobs.
2. Numbers 5 are given in the order of jobs in the exploded diagram. A number that is enclosed by a circle
indicates a disassembly step.
3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol marks 6 . The
meanings of the symbol marks are given on the next page.
4. A job instruction chart 7 accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc.
5. For jobs requiring more information, the step-by-step format supplements 8 are given in addition to the
exploded diagram and the job instruction chart.
2
1
4
5
8
6
6
7
3
EB003000
1
GEN
INFO
3
2
ILLUSTRATED SYMBOLS
SPEC
Illustrated symbols 1 to 9 are designed as
thumb tabs to indicate the chapter’s number and
content.
4
INSP
ADJ
ENG
5
6
COOL
CARB
7
ELEC
Illustrated symbols 10 to 17 are used to identify
the specifications appearing in the text.
10
9
TRBL
SHTG
11
12
13
14
16
10
11
12
13
14
15
16
17
17
18
19
20
21
22
23
24
General information
Specifications
Periodic inspection and adjustment
Engine
Cooling system
Carburetion
Chassis
Electrical
Troubleshooting
8
CHAS
15
1
2
3
4
5
6
7
8
9
25
Possible to maintain with engine mounted
Filling fluid
Lubricant
Special tool
Tightening
Wear limit, clearance
Engine speed
Ω, V, A
Illustrated symbols 18 to 23 in the exploded diagrams indicate the types of lubricants and lubrication points.
18
19
20
21
22
23
Apply engine oil
Apply gear oil
Apply molybdenum disulfide oil
Apply wheel bearing grease
Apply lightweight lithium-soap base grease
Apply molybdenum disulfide grease
Illustrated symbols 24 to 25 in the exploded diagrams indicate the where to apply locking agent
24 and when to install new parts 25 .
24 Apply locking agent (LOCTITE)
25 Use new one
CONTENTS
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ABS OUTLINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HU OPERATION TEST WHILE ABS IS WORKING . . . . . . . . . . . . .
YAMAHA ABS PROVIDES 3 MAIN ADVANTAGES . . . . . . . . . . . . .
SYSTEM LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TOTAL SYSTEM BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . .
COMPOSITION OF PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMPOSITION AND OPERATION OF PARTS . . . . . . . . . . . . . . . .
SYSTEM OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAUTION FOR OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1
1
3
3
4
4
5
10
13
14
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAINTENANCE SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHASSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ELECTRICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CABLE ROUTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
17
17
17
17
18
CHASSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ANTI-LOOK BRAKE SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TERMS EXPLANATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BRAKE FORCE AND THE VEHICLE STABILITY . . . . . . . . . . . . . . .
WHEEL SLIP AND THE HYDRAULIC CONTROL . . . . . . . . . . . . . .
ABS OPERATION AND THE VEHICLE CONTROL . . . . . . . . . . . . .
ELECTRONICS ABS FEATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ABS COMPONENTS FUNCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HYDRAULIC UNIT (HU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OTHER ABS MECHANISM COMPONENTS . . . . . . . . . . . . . . . . . . .
ABS TROUBLESHOOTING OUTLINE . . . . . . . . . . . . . . . . . . . . . . . .
ABS PARTS LOCATION CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ABS CONNECTOR LOCATION CHART . . . . . . . . . . . . . . . . . . . . . .
ABS CIRCUIT DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BASIC INSTRUCTION FOR TROUBLESHOOTING . . . . . . . . . . . .
BASIC PROCESS FOR TROUBLESHOOTING . . . . . . . . . . . . . . . .
ABS TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[A] MALFUNCTION CHECK BY THE ABS WARNING LIGHT . . . .
[B] DETAIL CHECK OF MALFUNCTION . . . . . . . . . . . . . . . . . . . . . .
[B-1] WARNING LIGHT DOES NOT GO ON . . . . . . . . . . . . . . . . . . .
[B-2] WARNING LIGHT REMAINS GOING ON . . . . . . . . . . . . . . . . .
[B-3] WARNING LIGHT KEEPS FLASHING . . . . . . . . . . . . . . . . . . .
[B-4] MALFUNCTION CHECK BY THE ABS SELF DIAGNOSIS
(PAST MALFUNCTION) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[B-5] MALFUNCTION CHECK BY THE ABS SELF DIAGNOSIS
(PRESENT MALFUNCTION) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[C] SUPPOSING THE MALFUNCTION CAUSE AND POSITION .
27
27
27
28
29
29
30
31
34
35
37
39
40
41
42
43
44
44
44
44
44
44
45
46
47
[C-1] ONLY ABS WARNING LIGHT DOES NOT GO ON WHEN
THE MAIN SWITCH IS TURNED ON . . . . . . . . . . . . . . . . . . . . . . . . .
[C-2] ABS WARNING LIGHT AND ALL OTHER INDICATORS
DO NOT GOES ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[C-3] ABS WARNING LIGHT KEEPS FLASHING . . . . . . . . . . . . . . .
[C-4] ABS WARNING LIGHT FLASHES EVERY 0.5 SECOND . . .
[C-5] DIAGNOSIS BY THE MALFUNCTION CODE . . . . . . . . . . . . .
ECU AND FAIL SAFE RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[D-1] MAINTENANCE FOR ECU . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[D-2] MAINTENANCE OF THE ABS FAIL-SAFE RELAY . . . . . . . . .
FRONT WHEEL SENSOR AND SENSOR ROTOR . . . . . . . . . . . . .
[D-3] MAINTENANCE OF THE FRONT WHEEL SENSOR AND
SENSOR ROTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REAR WHEEL SENSOR AND SENSOR ROTOR . . . . . . . . . . . . . .
[D-4] MAINTENANCE OF THE REAR WHEEL SENSOR AND
SENSOR ROTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HYDRAULIC UNIT (HU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[D-5] MAINTENANCE OF THE HYDRAULIC UNIT (HU) . . . . . . . . .
AIR BLEEDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHECK THE OPERATION OF HYDRAULIC UNIT
ACCORDING TO THE DECOMPRESSION . . . . . . . . . . . . . . . . . . .
[D-6] FINAL CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[D-6-1] CHECKING THE RESERVOIR TANK FLUID LEVEL . . . . .
[D-6-2] RECHECKING THE ASSEMBLY STATUS OF
WHEEL SENSORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[D-6-3] HU OPERATION TEST 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[D-6-4] DELETING THE MALFUNCTION CODE . . . . . . . . . . . . . . .
[D-6-5] TRIAL RUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REAR SHOCK ABSORBER AND SWING ARM . . . . . . . . . . . . . . . . . . .
YP250A ’99 WIRING DIAGRAM
47
48
48
49
50
60
61
62
64
65
69
70
72
73
78
78
78
79
79
80
82
83
84
ABS OUTLINE
GEN
INFO
GENERAL INFORMATION
ABS OUTLINE
Introduction
YP250A is equipped with the ABS (Anti-lock Brake System).
HU OPERATION TEST WHILE ABS IS WORKING
With the scooter stopped, YP250A allows a driver to test the performance of brake lever reaction force
which is generated when the ABS operates.
There are two methods for the HU operation test, but this section describes only about the HU operation test 1.
HU operation test 1: Equal reaction force to the time of ABS operation is generated on the lever.
HU operation test 2: Mainly performs when checking the function after the ABS system has been disassembled, adjusted and serviced. Refer to [D-6-3] HU operation test 2.
HU operation test 1
1. Turn the main switch off.
2. Remove the protective cap and insert the test
coupler adapter 1 into the test connector 2 .
Test coupler adapter
90890-03149
NOTE:
To access the test coupler, remove the lower panel of windscreen.
3. Turn the engine stop switch 1 off.
1
ABS OUTLINE
GEN
INFO
4. Turn the main switch on.
NOTE:
Wait until the ABS warning light goes off after turning the main switch on.(2 seconds)
5. Turn on the starter switch 1 for longer than 4
seconds.
CAUTION:
Do not grip the brake lever in this case.
6. After releasing the starter switch (OFF), apply
the front brake lever.
Reaction force is generated on the front brake
lever 0.5 second later and lasts about 2 seconds.
7. If the reaction force of front brake lever is lost,
apply the rear brake lever while applying the
front brake lever.
Reaction force is generated on the front brake
lever 0.5 second later and lasts about 2 seconds.
8. Turn the main switch off.
9. Remove the test coupler adapter from the test
connector.
10. Turn the main switch on.
11. Set the engine stop switch to RUN position.
2
ABS OUTLINE
GEN
INFO
YAMAHA ABS PROVIDES 3 MAIN ADVANTAGES
1. Securely controls the wheel locking at urgent braking under various conditions of road surface and
weather, and gives full play to tires’ original performance.
For higher reliability, the electronic control unit (ECU) is composed of the main and sub processors and
equipped with the high level self diagnostic function.
2. Smooth braking can be also performed when the ABS system is activated. Change of chassis behavior
such as pitching is few and this system will not damage the rider’s comfortable drive feeling.
When the ABS works, the system informs the brake fluid pressure change to a rider via brake levers.
3. Weight of the hydraulic unit (HU) which is the main of system is 2.2 kg for YAMAHA ABS. We designed to
gather the mass by locating this unit at the central portion of scooter. Since the wheel assembly (wheel
sensor) also has extremely lightweight structure, the vehicle’s weight gives no damage to the mobility
which YP250A provides such as an excellent safety operation.
SYSTEM LAYOUT
1 ABS warning light
2 Front / Rear master cylinders
Front / Rear brake levers
Front / Rear brake switches
3 Fail-safe relay
4
5
6
7
8
Brake light relay
Rear brake caliper
Rear wheel sensor
Electronic control unit
Rear disc rotor
3
9
10
11
12
Hydraulic unit
Front brake caliper
Front wheel sensor
Front disc rotor
ABS OUTLINE
GEN
INFO
TOTAL SYSTEM BLOCK DIAGRAM
1
2
3
4
5
6
7
Rear master cylinder
Hydraulic unit
Silencer chamber
Hydraulic pump
Electric motor
Buffer chamber
Hydraulic control valve
8
9
10
11
12
13
14
Front master cylinder
Rear brake caliper
Front brake caliper
Electronic control unit
Rear wheel sensor
Front wheel sensor
ABS warning light
COMPOSITION OF PARTS
Component
Function
Wheel sensor
Detects each wheel rotation pulse of front and rear wheels
and inputs them to the electronic control unit.
ABS warning light
Warns the ABS system failure to the rider.
Fail-safe relay
Supplies the power to the solenoid valve and motor of hydraulic unit.
Hydraulic unit (HU)
Controls the brake fluid pressure of front and rear wheels according to the output signal sent from the electronic control
unit.
Electronic control unit (ECU)
Outputs the operation signal to the hydraulic unit so that the
unit controls matching the road conditions according to the
wheel rotation pulses transmitted from front and rear wheel
sensors.
In case of ABS system failure, the unit activates the ABS
warning light and shuts off the power to hydraulic unit and
deactivates the ABS operation.
4
ABS OUTLINE
GEN
INFO
COMPOSITION AND OPERATION OF PARTS
1. Wheel sensor and sensor ring
A wheel sensor is composed of magnet and coil
and installed with front and rear wheels’ housings.
The sensor ring attached to front and rear cast
wheels have 36 serration each. The front end of
wheel sensor is close to the serration.
When the sensor rotor with serration rotates, the
flux generation from the wheel sensor magnet
changes to generate the alternating voltage in the
coil. The electronic control unit calculates the
wheel speed by detecting the repeating times per
unit period since this alternating voltage changes
the frequency proportioning to the wheel rotation
speed.
1
2
3
4
At high speed
At low speed
Wheel sensor
Sensor rotor
2. ABS warning light
If the failure occurred in the ABS system, the ABS
warning light alerts the rider by going on the ABS
warning light.
When the main switch is turned on, the system
goes on the light for about 2 seconds to check the
disconnection of ABS warning light and system
function, then it goes off.
It goes on while the starter switch is pushed to
check the disconnection.
CAUTION:
If the rear wheel is raced by lifting with the centerstand or other means, the system may
judge as the malfunction to flashes or goes on
the ABS warning light.
In this case, turn the main switch off once and
restart the engine.
The system is normal if the ABS warning light
goes on and off in about 2 seconds.
1 ABS warning light
5
ABS OUTLINE
GEN
INFO
3. Hydraulic unit
Hydraulic unit is composed of two pieces of hydraulic control valve (solenoid valve, flow control
valve), buffer chamber, pump and silencer chamber, and one motor. It adjusts the front/rear wheel
brake fluid pressure to control the wheel rotation
condition according to the signal sent from the
electronic control unit.
1
2
3
4
5
To rear brake master cylinder
Silencer chamber
Hydraulic pump
Electric motor
Buffer chamber
6
7
8
9
10
6
Hydraulic control valve
To front brake master cylinder
To the rear brake caliper
To the electronic control unit
To the front brake caliper
ABS OUTLINE
GEN
INFO
Hydraulic control valve
Hydraulic control valve is composed of the solenoid valve and flow control valve.
1) When the normal brake is applied, the solenoid
valve closes 2 , the spool 3 of flow control
valve does not move and the hydraulic line between the master cylinder and brake caliper is
opened.
2) While the ABS works, the solenoid valve 2 is
supplied the power to open when the electronic
control unit signals the pressure reduction and
the spool 3 of flow control valve is moved toward to the solenoid valve.
3) When the electronic control unit stops the signal of pressure reduction, the solenoid valve
2 closes and pressurizing starts again. Repressurizing while the ABS works controls the
flow of brake fluid by the movement of spool 3
of flow control valve, and provides slow pressure rising.
1
2
3
4
Orifice
Solenoid valve
Spool
Flow control valve
Buffer chamber
Accumulates the decompressed brake fluid temporarily while the ABS works.
1 Buffer chamber (in normal state)
2 Buffer chamber (decompressing)
3 Raise the piston
7
ABS OUTLINE
GEN
INFO
4. Electronic control unit
Relation of the input signal and output signal is shown in the diagram.
The circuit receives the signals from wheel sensors, processes them according to the programs in the microcomputer and outputs the control signal to the hydraulic unit and ABS warning light.
Electronic control unit (ECU)
Power
Voltage
regulator
Memory
Front brake
switch signal
Rear brake
switch signal
Stop lamp
signal
Solenoid
motor
Front brake
switch
circuit
Rear brake
switch
circuit
Motor monitor
circuit
Solenoid drive
circuit
Fail-safe relay
drive circuit
Main CPU
(Main microcomputer)
Motor
Hydraulic
unit (HU)
Solenoid
Motor relay
Motor relay
drive circuit
Warning light
drive circuit
Brake
light circuit
Solenoid valve
ABS warning light
Operation mode
switching circuit
Starter
switch
signal
Starter switch
Starter
switch
circuit
Fault code
output circuit
Checker
Front
wheel sensor
Rear
wheel sensor
Front wheel speed
output circuit
Digital
conversion
circuit
Sub CPU
(Sub microcomputer)
8
Speedometer
Fail-safe
relay
ABS OUTLINE
GEN
INFO
5. Fail-safe relay
Fail-safe relay controls the power of hydraulic unit
and it is located inside of the tail cover.
1 Fail safe relay
Composition and operation
Fail-safe relay is composed of the solenoid relay 1 and motor relay 2 .
Solenoid relay is continued when the electronic control unit outputs the system start signal. Accordingly, the
solenoid valve 3 is activated when the electronic control unit signals the decompression.
In case of malfunction, the solenoid relay is turned off and the solenoid valve is deactivated.
This makes it impossible to reduce the hydraulic pressure and resumes normal braking. Motor relay is also
continued by the signal of electronic control unit and starts the motor simultaneously when the ABS pressure reduction begins.
When the solenoid is turned off, the motor relay is also turned off, therefore the motor stops its operation in
case of malfunction.
1
2
3
4
5
Solenoid relay
Motor relay
Solenoid valve
Electric control unit
Pomp motor relay coil
6
7
8
9
10
Pump motor monitor
ABS warning light
Fail-safe relay coil
Front solenoid
Rear solenoid
9
11 Power
12 Fail-safe relay
13 Hydraulic unit
GEN
INFO
ABS OUTLINE
SYSTEM OPERATION
ABS system’s fluid pressure circuit has the 2 lines of front wheel and rear wheel systems. In this section, we
describe about one system of a front wheel.
Normal brake (ABS not activated)
Port D 12 of the solenoid valve is closed since the control signal from the electronic control unit is not sent to
the hydraulic unit. A 8 and B 10 ports of flow control valve spool are opened.
Accordingly, when a rider apply the brake lever and the master cylinder hydraulic pressure rises, the brake
fluid is directed in the line from Port A 8 to Port B 10 then to brake caliper.
At this time, inlet and outlet check valves of pump close the lines and brake fluid is not sent. Therefore, master cylinder directly pressurizes the brake caliper while braking normally.
When the brake lever is released next, the brake fluid in the brake caliper returns then to the master cylinder
via Port B 10 , Port A 8 .
1 Brake master
2
3
4
5
6
7
8
9
10
10
cylinder
Brake switch
Silencer chamber
Motor
Pump
Buffer chamber
Flow control valve
Port A
Spool
Port B
11
12
13
14
15
16
17
18
19
20
Orifice
Port D
Solenoid valve
Port C
Brake caliper
Electronic control
unit
ABS warning light
Brake fluid pressure
Time
Repressurizing
GEN
INFO
ABS OUTLINE
At the time of urgent braking (When ABS works)
1) Decompressed state
When the wheel is almost locked, the solenoid valve’s port D 12 opens by the “decompression” signal
from the electronic control unit. At this time, the spool 9 of flow control valve compresses the return
valve to close the port B 10 .
Brake fluid which has entered through port A 8 is restricted by the orifice 11 .
Accordingly, the brake fluid from the brake caliper is sent in the line of Port C 14 , Port D 12 then to the
buffer chamber 6 .
The brake caliper fluid pressure is now reduced.
Brake fluid which has been stored in the buffer chamber is pumped by the fluid pressure pump interlocked with motor and returned to the master cylinder.
1 Brake master
2
3
4
5
6
7
8
9
10
11
cylinder
Brake switch
Silencer chamber
Motor
Pump
Buffer chamber
Flow control valve
Port A
Spool
Port B
11
12
13
14
15
16
17
18
19
20
Orifice
Port D
Solenoid valve
Port C
Brake caliper
Electronic control
unit
ABS warning light
Brake fluid pressure
Time
Repressurizing
GEN
INFO
ABS OUTLINE
2) Pressurized state
Port D 12 of solenoid valve closes according to the “increase pressure” signal from the electronic control
unit. Also, spool 9 of flow control valve compresses the return spring to close the port B 10 .
Brake fluid entered through port A 8 is further restricted by the orifice 11 .
Accordingly, the brake fluid in master cylinder is sent in the line of Port A 8 , Port C 14 then to the brake
caliper. However, the brake is pressurized at a constant speed regardless of the brake fluid pressure
level since the port A’s 8 restriction changes so that the constant pressure difference is maintained between A 21 and B 22 chambers of flow control valve.
1 Brake master
2
3
4
5
6
7
8
9
10
11
12
cylinder
Brake switch
Silencer chamber
Motor
Pump
Buffer chamber
Flow control valve
Port A
Spool
Port B
Orifice
12
13
14
15
16
17
18
19
20
21
22
Port D
Solenoid valve
Port C
Brake caliper
Electronic control
unit
ABS warning light
Brake fluid pressure
Time
Repressurizing
Chamber A
Chamber B
ABS OUTLINE
GEN
INFO
CAUTIONS FOR OPERATION
The YAMAHA ABS applies the double system control type with the independent hydraulic system for the
front and rear wheels respectively.
Accordingly, the brake operation is the same as usual scooters providing the right hand brake lever to be
used for the front wheel and left hand brake lever for the rear wheel.
When the locking tendency of wheels due to urgent brake is detected on each wheel, the independent hydraulic control is performed by each brake hydraulic system.
The YAMAHA ABS controls the hydraulic pressure by electronic controls.
With the main switch turned on, when the electronic control unit always operates the wheel’s locking movement and checks the system function simultaneously.
If the failure such as a malfunction occurs to the ABS or peripheral electric system, the scooter automatically
shifts to apply the normal brake function.
If the ABS warning light goes on:
When the main switch is turned on, the ABS warning light goes on for about 2 seconds.
While pressing the starter switch, the ABS warning light and engine oil level warning light goes on.
If the ABS warning light goes on during the riding, stop the scooter at the safe place, stop the engine and
turn the main switch off. Turn the main switch on again. It is normal if the ABS warning light goes on and
off in about 2 seconds.
Even if the ABS warning light keeps going on and will not go off, or it goes on again after riding, the
vehicle’s performance as a normal brake is still maintained.
If the rear wheel is raced, the ABS system may judge as the malfunction to flashing or goes on the ABS
warning light. In this case, turn the main switch off once. Then, turn on again. The ABS system is normal
if the ABS warning light goes on and off in about 2 seconds.
ABS works normal when the ABS warning light flashings.
ABS function:
ABS is not designed to shorten the braking distance or improve the cornering performance.
The braking distance may become longer in comparison with scooters without ABS depending on the
road condition, keep a lower speed and safe distance between yourself and the other vichicls.
It is basic for a scooter to brake while driving straight. Sudden braking while cornering affects the motion
characteristics of chassis. Avoid it.
Brake system in which the hydraulic control has been performed by the ABS system alerts a rider that
the wheel had an inclination to lock by returning the reaction force to the brake lever. In this case, this
condition is a sign that the grip between road surface and tires had come close to the limit point. The rear
wheel’s locking state* which occurs when the strong engine brake is applied on the slippery road is beyond the ABS control range. In these cases, drive the vehicle carefully.
The ABS does not work when the main switch is turned off. It becomes the normal braking function.
* Locking state: By braking stronger than the tires’ gripping force, the chassis moves forward but the wheels
do not rotate.
13
SPECIAL TOOLS
GEN
INFO
EB104000
SPECIAL TOOLS
The following special tools are necessary for complete and accurate tune-up and assembly.
Use only the appropriate special tools as this will help prevent damage caused by the use of inappropriate tools or improvised techniques.
When placing an order, refer to the list provided below to avoid any mistakes.
Tool No.
Tool name/Function
Test coupler adaptor
90890-03149
This tool is used to check the ABS diagnosis.
14
Illustration
GENERAL SPECIFICATIONS
SPEC
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model
Model code:
YP250A
5DF3 (except for CH)
5DF4 (for CH)
Dimensions:
Overall length
Overall width
Overall height
Seat height
Wheelbase
Minimum ground clearance
Minimum turning radius
2,110 mm
,780 mm
1,330 mm
,700 mm
1,500 mm
,115 mm
2,600 mm
Basic weight:
With oil and full fuel tank
169 kg
Transmission:
Primary reduction system
Primary reduction ratio
Secondary reduction system
Secondary reduction ratio
Transmission type
Operation
Single speed automatic
Helical gear
40/15 (2.667)
Sper gear
38/15 (2.533)
Single speed automatic (V-belt type)
Centrifugal automatic type
2.34 0.82 : 1
Tire pressure (cold tire):
Maximum load-except motorcycle
Loading condition A*
front
rear
Loading condition B*
front
rear
High-speed riding
front
rear
Brake:
Brake control device
Front brake
type
operation
Rear brake
type
operation
186 kg
0 90 kg
175 kPa (1.75 kg/cm2, 1.75 bar)
200 kPa (2.0 kg/cm2, 2.0 bar)
90 186 kg
200 kPa (2.0 kg/cm2, 2.0 bar)
225 kPa (2.25 kg/cm2, 2.25 bar)
200 kPa (2.0 kg/cm2, 2.25 bar)
250 kPa (2.5 kg/cm2, 2.5 bar)
ABS
Single disc brake
Right hand operation
Single disc brake
Left hand operation
* Load is the total weight of cargo, rider, passenger, and accessories.
15
GENERAL SPECIFICATIONS
Model
Bulb wattage
quantity:
Headlight
Marker light
Tail/brake light
Flasher light
Meter light
High beam indicator light
Oil indicator light
Turn indicator light
ABS warning light
License light
YP250A
12 V 60 W/55 W
12 V 5 W
1
12 V 5 W/21 W
12 V 21 W
4
12 V 1.7 W
4
12 V 1.7 W
1
12 V 1.7 W
1
12 V 3.4 W
2
LED
1
12 V 5 W
1
16
1
1
SPEC
MAINTENANCE SPECIFICATIONS
SPEC
MAINTENANCE SPECIFICATIONS
ENGINE
Item
Standard
Limit
Carburetor:
Type
I.D. mark
Ventuly outside diameter
Main jet
Main air jet
Jet needle
Throttle valve size
Pilot air jet
Needle jet
Pilot outlet
Pilot jet
Bypass
Pilot screw
Valve seat size
Starter jet 1
Starter jet 2
Float height
Engine idle speed
Intake vacuum
Oil temperature
Cooling water temperature
Y28V-1A
4UC 03 [4UD 03 (CH)]
ø 28
# 130
ø 0.9
5D32-3/5
11_
ø 1.2
# 85
ø 0.8
# 44
0.7
3
1 7/8 [1 5/8 (CH)]
1.4
ø 0.45 [ø0.47 (CH)]
ø 0.5
27 mm
1,350 X 1,450 r/min
220 X 260 mmHg
65 X 75_C
80_C
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
Item
Standard
Limit
Rear disc brake:
Type
Disc outside diameter
thickness
Pad thickness
Master cylinder inside diameter
Caliper cylinder outside diameter
Brake fluid type
Single
230
5.0 mm
5.3 mm
11 mm
22.2 + 22.2 mm
DOT #4
SSS
SSS
0.8 mm
SSS
SSS
SSS
Standard
limit
Fuse
20 A
3A
30 A
5A
20 A
3A
30 A
5A
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
(M.J)
(M.A.J)
(J.N)
(Th.V)
(P.A.J.1)
(N.J)
(P.O)
(P.J)
(B.P)
(P.S)
(V.S)
(G.S.1)
(G.S.2)
(F.H)
CHASSIS
ELECTRICAL
Item
Circuit breaker:
Type
MAIN
FAN
ABS motor
ABS
Reserve
1 pc.
1 pc.
1 pc.
1 pc.
1 pc
1 pc.
1 pc.
1 pc.
17
CABLE ROUTING
SPEC
CABLE ROUTING
1
2
3
4
5
6
7
8
9
Front wheel sensor lead
Wireharness (ABS)
Rear wheel sensor lead
Carburetor drain hose
Carburetor coolant drain hose
Carburetor air ventilation hose
Fail safe relay
Brake light relay
Electronic control unit (ECU)
10
11
12
13
14
15
16
17
18
Rear wheel sensor
Crankcase
Over flow hose (fuel filler)
Hydraulic unit
Down tube
Wireharness
Steering head pipe
Throttle cable
Crankcase breather hose
18
A Route the rear brake hose through
the guide on the handlebar holder.
B Fasten the wireharness to the stay
with a plastic band.
Refer to fig D.
C Fasten the throttle cables and
wireharness to the down tube with
a plastic band.
Refer to fig A.
CABLE ROUTING
D Align the mark on the brake hoses
with clamp, and clamp them.
E Fasten the throttle cable to the
frame with a plastic band.
Refer to fig B.
F Route the fuel tank over flow hose
through the clamp on inside of the
frame.
G Lower throttle cable is pull side.
H Upper throttle cable is push side.
I Fasten the wireharness with a
steel clamp on the frame.
J Route the rear wheel sensor as
illustration.
K Route the rear wheel sensor lead
through the guide.
L Route the carburetor air ventilation hose, carburetor coolant drain
hose and carburetor drain hose
through the guide.
M Route the carburetor drain hose
through the guide.
N Route the over flow hose (fuel filler) and hydraulic unit drain hose
through the guide.
19
SPEC
O Position the connector of plastic
band as illustration.
P Position the connector of the plastic band inside of the line.
Q Route the rear wheel sensor lead
through the front of the crankcase
breather hose.
R Align the white tape on the wireharness with the steel clamp on
the frame, and fasten them.
CABLE ROUTING
1
2
3
4
5
6
7
8
9
10
Box light
Rectifier / regulator
Fuel sender
Ignition coil
Roll over valve
Seat lock cable
Handlebar switch lead (right)
Front brake switch lead
Front brake hose
Reservoir tank hose
11
12
13
14
15
16
17
18
19
20
Starter switch
Battery
Flasher relay
Coolant reservoir tank
Crankcase breather hose
Air filter case
Front brake hose (IN)
Front brake hose (OUT)
Rear brake hose (IN)
Hydraulic unit coupler
20
21
22
23
24
25
26
27
28
29
SPEC
Rear brake hose (OUT)
Igniter
Down tube
Wireharness
Rear brake hose
Battery leads
AC magneto lead
Starter motor lead
Engine ground lead
CABLE ROUTING
A Route the box light lead through
from the outside of the frame to the
inside of the pipe.
B Connect the taillight lead and wireharness on the mudguard.
C Fasten the fuel sender lead to the
pipe with a plastic clamp.
D Fasten the fuel sender lead and
auto choke lead with a steel clamp
on inside of the frame.
E Fasten the seat box light switch
lead to the hinge with a plastic
locking tie. Route the plastic locking tie into the hole and under the
projection of hinge.
F Route the box switch lead under
the projection of fuel tank hinge.
G Route the box switch lead from
outside of the fuel tank over flow
hose to inside of the pipe.
H Fasten the electronic control unit
leads (3 lines) with a plastic band.
21
SPEC
I Route the seat lock cable through
the pipe, and align the mark of seat
lock cable with the pipe end.
J Fasten the wireharness and seat
lock cable with a steel band on the
frame.
K Position the junction of the thermo
switch lead inside of the scooter.
L Align the location tape with the
steel clamp on the frame, and fasten them.
CABLE ROUTING
M Fasten the wireharness, seat lock
cable and pipe with a steel clamp
on the frame.
N Fasten the front wheel sensor lead
and front brake hose with a plastic
clamp. Position the clamp (location of the front wheel sensor) to
front of the upper clamp and
another clamps to outside.
O Route the front wheel sensor lead
between the caliper and caliper
bolt. Do not route as dotted line.
SPEC
P Route the front wheel sensor lead U Fasten the wireharness to the
through the guide.
frame with a plastic band.
Q Fasten the pipe with a steel clamp V Route the brake hose, wireharon the frame.
ness and battery leads through the
R Fasten the fan motor lead, sideguide.
stand switch lead and starter W Fasten the battery leads and wireswitch lead to the frame with a
harness with a steel clamp on the
plastic band.
frame.
S Route the wireharness over the X Fasten the wireharness with a
rear brake hose.
steel clamp on the frame.
T Route the coolant reservoir tank Y Position the connector of plastic
over flow hose through the guide
band as illustration.
on the inside of the frame.
Z Clearance: 1 mm or more
22
CABLE ROUTING
1
2
3
4
5
6
7
8
9
10
11
12
Seat lock
Air filter case
Engine ground lead
Crankcase breather hose
Fuel hose
Vacuum hose
Sidestand switch lead
Fan motor lead
Fuel tank over flow hose
Reservoir tank breather hose
Starting circuit cutoff relay
Auto choke lead
13
14
15
16
17
18
AC magneto lead
Starter motor lead
Seat lock cable
Fuel pump
Fuel tank
Hydraulic unit
A Route the hydraulic unit drain
hose under the coolant hose.
B Fasten the fuel tank over flow hose
with a steel clamp on the frame.
23
SPEC
C Fasten the sidestand switch lead
with a steel clamp on the frame.
D Route the thermo switch lead outside of the frame.
E Fasten the wireharness to the
frame with a plastic band.
F Route the battery positive lead as
illustration.
G Fasten the thermo switch lead and
fan motor lead with a steel clamp
on the frame.
CABLE ROUTING
H Fasten the sidestand switch lead
and battery positive lead with a
steel clamp on the frame.
I Fasten the sidestand switch lead
with a plastic clamp.
J Route the battery negative lead
through the front and lower side of
the flasher relay.
K Fasten the wireharness, AC magneto lead, starter motor lead and
engine ground lead with a steel
clamp on inside of the frame.
L Fasten the AC magneto lead,
starter motor lead and engine
ground lead with a steel clamp on
the engine bracket.
M Route the crankcase breather
hose into the hole of air filter case.
N Route the fuel hose over the vacuum hose.
O Position the end of the clip to outside.
P Fasten the front wheel sensor and
electronic control unit lead to the
frame with a plastic band.
24
SPEC
Q Install the fuse box to the stay on
the frame.
R Fasten the front wheel sensor,
fuse lead and electronic control
unit lead to the frame with a plastic
band.
S Do not fasten the fuel tank over
flow hose with a plastic band.
CABLE ROUTING
1
2
3
4
5
6
7
8
9
10
11
12
Front turn signal light (right)
Front turn signal light (left)
Handlebar switch lead (right)
Front stop switch lead
Seat lock cable
Throttle cable
Handlebar switch lead (left)
Rear brake switch lead
Handlebar under cover
Stay
Horn
Front brake hose
13
14
15
16
17
18
19
Front wheel sensor
Horn
ABS test terminal
Handlebar upper cover
Handlebar
Front turn signal light
Grip heater lead (option)
A Route the front wheel sensor
through the guide on the frame.
B Route the handlebar switch lead
and front brake switch lead
through the guide.
25
SPEC
C Route the front brake hose
through the right hole of the handlebar under cover.
D Route the rear brake hose through
the left hole of the handlebar under
cover.
E Fasten the handlebar switch lead
(left) and rear brake switch lead to
the handlebar with a plastic locking tie. Cut the end of locking tie at
5 mm or less.
CABLE ROUTING
F Route the handlebar switch (left)
lead and rear brake switch lead
through the left side of the
speedometer cable.
G Route the front wheel sensor
through the guide.
H Fasten the front brake hose with a
brake hose holder.
I Fasten the headlight lead, horn
lead and front wheel sensor lead
with a steel clamp on the stay.
J Route the handlebar switch (left)
lead through the front side of the
handlebar under cover.
26
SPEC
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
CHASSIS
ANTI-LOCK BRAKE SYSTEM
The YAMAHA ABS is the electronic control system applying the 2 system control type with the independent hydraulic system for the front and rear
wheels respectively.
Accordingly, the brake operation is the same as
usual scooters providing the right hand brake lever to be used for the front wheel and left hand
brake lever for the rear wheel.
When the locking movement of wheels due to urgent braking is detected on each wheel, the independent hydraulic control is performed by each
brake hydraulic system.
TERMS EXPLANATION
Wheel speed
Rotation speed of front and rear wheels itself is
the wheel speed.
Chassis speed
When the brake is applied, the wheel rotation is
lowered and the chassis speed reduces. However, the chassis tends to travel forward by its inertia even though the wheel rotation is lowered.
The speed of chassis itself is the chassis speed.
Brake force
This is the force to reduce the speed by braking.
Wheel lock
On a slippery road, if the brake was applied too
strong the vehicle tends to run on, but the wheels
stop rotating. This state is called a wheel lock.
Side force
This is the force to act on tires which supports the
vehicle sideways.
27
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Slip ratio
When the brake is applied, slipping occurs between tires and road surface, then the difference
is made between the wheel speed and chassis
speed. This is called a slip.
Slip ratio is the value to show the rate of slipping
and defined by the following formula.
Slip ratio =
Chassis speed – Wheel speed
Chassis speed
100 (%)
0%:
There is no slip between wheels and road
surface providing the complete rotation
of wheels.
100%: The wheel speed is “0”, i.e. the state of
wheel locking.
A
BRAKE FORCE AND THE VEHICLE STABILITY
When the brake pressure is increased, it brakes
the wheel and the slip occurs between the tire and
road surface to generate the brake force. The limit
of this brake force is determined by the friction
force between the tire and road surface and has a
close relation with the state of slipping. Slipping
state is shown by the slip ratio.
Therefore, the side force has also a close relation
with the slipping state . Figure A shows the relation of them. If the vehicle is braked while keeping
the proper slip ratio, it is possible to gain the maximum brake force without losing the much side
force.
The ABS has a function which allows these tire
characteristics to bring their ability into full play on
the slippery or less-slippery road. (Figure B )
Friction force between the
tire and road surface
Brake force
Side force
Slip ratio(%)
Friction force between the
tire and road surface
B
Less slippery
road surface
Controlling zone
Slippery road surface
Slip ratio(%)
28
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
WHEEL SLIP AND THE HYDRAULIC CONTROL
The ABS computer calculates each wheel speed
according to the rotation signal receiving from the
front and rear wheel sensors. In addition, the computer calculates the vehicle travel speed and rate
of speed reduction with wheels based on the
wheel speed values.
Differences between the travel speed and wheel
speed of wheels calculated as above are equal to
the wheel slip. When the wheel tends to lock, the
wheel suddenly reduces its speed. When the slip
of wheel and speed reduction rate of wheel exceeds the preset value, the ABS computer judges
that the wheel is in the tendency to lock. If the slip
is large and the wheel tends to lock (A point in the
figure), the ABS computer decompresses the
brake fluid of caliper and increases the pressure
when the locking tendency disappears (B point in
the figure).
If slip is large and the wheel tends to lock (A point
in the figure), the ABS computer executes the
pressure reduction and increases the pressure
when the locking tendency disappears (B point in
the figure).
Vehicle speed
Wheel speed
Pressurizing
Decompressing
Brake force
ABS OPERATION AND THE VEHICLE CONTROL
When the ABS is activated, it means that the
wheel has a tendency to lock and the vehicle control is close to its limit. To recognize this vehicle
condition, the brake lever is designed to generate
the reaction force.
NOTE:
Reaction force to the brake lever while the ABS
works is normal.
29
ANTI-LOCK BRAKE SYSTEM (ABS)
Side force also reduces when the vehicle
equipped with the ABS is braked as same as vehicles with ordinary brake system. Accordingly,
sudden braking while cornering loses the vehicle’s stability regardless of ABS existence. It is
not the ABS function to prevent the vehicle from
slipping to sideways.
Brake force
Friction force between the
tire and road surface
CHAS
Side force
WARNING
Slip ratio(%)
It is basic for a scooter to brake while driving
straight. Even the ABS equipped scooter cannot stop slipping sideways by losing its stability due to sudden brake while cornering.
The function of ABS works to control the brake’s
hydraulic pressure and prevent the wheel’s locking tendency.
Accordingly, locking of wheels which may occur
when the engine brake is applied on the slippery
road is beyond the ABS control range.
WARNING
Even the ABS equipped scooter cannot prevent the locking tendency of wheels on the extremely slippery road caused by the engine
brake.
ELECTRONICS ABS FEATURE
The YAMAHA ABS is the anti-lock brake system
developed under the most advanced electronics
technology.
The control is processed with good response providing various travel conditions for scooters.
The system also equipments the highly developed
self diagnostic function and designed to return to
the normal braking state by detecting the problem
condition correctly even if the vehicle is struck by
troubles.
At the moment, the ABS warning light of meter
panel alerts a drive by goes on.
The YAMAHA ABS is designed to restore the
trouble history in the memory allowing easy troubleshooting by reading the malfunction code.
30
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
The ABS is composed of major components as
follows.
Front and rear wheels are equipped with sensors
and sensor rotors respectively.
1 Wheel sensor and the sensor rotor
2 Electronic control unit (ECU)
3 Hydraulic unit (HU)
4 Fail-safe relay
5 ABS harness
In addition, there are relevant parts such as the
ABS warning light in the meter panel, the test connector of ABS harness in the cowling body.
CAUTION:
Care should be taken to handle the ABS components since they have been accurately adjusted and must be kept away from shocks
and dirt.
Among the ABS components, parts of the
ECU, HU, wheel sensor and fail-safe relay
cannot be disassembled.
ABS COMPONENTS FUNCTION
Wheel sensor and the sensor rotor
Wheel sensor 1 detects the wheel rotation speed
and works to send the wheel rotation signal to the
ECU.
It is composed of the permanent magnet and coil.
For a front wheel, it is attached to the sensor housing 2 and to the crankcase for a rear wheel.
Sensor rotor 3 is pressed in the inner side of
wheel hub with front and rear wheels, then rotates
together with the wheel. Sensor rotor has 36
serration inside and is installed close to the wheel
sensor. Accordingly, the distance changes to the
crest and bottom of teeth as the wheel rotates to
generate the inductive electromotive force in the
wheel sensor. Wheel rotation speed can be thus
detected based on the frequency of this alternating voltage.
31
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Electronic control unit (ECU)
Electronic control unit 1 controls the ABS and is
installed inside the taillight unit. To protect from
water invasion, it is enveloped by a cover 2 .
As shown in the block diagram below, the ECU
takes in the wheel sensor signals from front and
rear wheels and also receives the signals from
various monitor circuits. Two of main and sub microcomputers are installed in the ECU providing
mutual monitoring.
Electronic control unit (ECU)
Power
Voltage
regulator
Memory
Front brake
switch signal
Rear brake
switch signal
Stop lamp
signal
Solenoid
motor
Front brake
switch
circuit
Rear brake
switch
circuit
Motor monitor
circuit
Solenoid drive
circuit
Fail-safe relay
drive circuit
Main CPU
(Main microcomputer)
Motor
Hydraulic
unit (HU)
Solenoid
Motor relay
Motor relay
drive circuit
Warning light
drive circuit
Brake
light circuit
Solenoid valve
ABS warning light
Operation mode
switching circuit
Starter
switch
signal
Starter switch
Starter
switch
circuit
Fault code
output circuit
Checker
Front
wheel sensor
Rear
wheel sensor
Front wheel speed
output circuit
Digital
conversion
circuit
Sub CPU
(Sub microcomputer)
32
Speedometer
Fail-safe
relay
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
The operation result is confirmed by the monitor
circuit. Based on the result, the control signals of
hydraulic unit (HU) and fail-safe relay will be issued.
ABS control operation
The ABS control operation performed in ECU is divided into 2 parts as follows.
Soft wear operation flow
Turn the main switch on
1 Hydraulic control
2 Self diagnosis
These operations will be performed repeating one
time in every 8/1000 seconds. In the case of failure occurrence, it is stored in the malfunction code
memory allowing easy find and check of failures.
Initialize
Self diagnosis
(at static)
NOTE:
Depending on the type of failure, it will not be recorded in the memory. (e.g. battery voltage drop)
Self diagnosis
(at riding)
Receive the signals
8 / 1000
seconds
Control operation
Judge of decompressing /
pressurizing
Hydraulic unit (HU)
This hydraulic unit (HU) 1 is the component to
control the hydraulic pressure of brake system under the signal of ECU, and located beside the battery box at the center of scooter central part.
33
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
HYDRAULIC UNIT (HU)
Hydraulic unit is composed of two pieces of hydraulic control valve (solenoid valve, flow control valve), buffer chamber, pump and silencer chamber, and one motor. It adjusts the front/rear wheel brake fluid pressure
to control the wheel rotation condition according to the signal transmitted from the electronic control unit.
1 Rear master
2
3
4
5
6
7
8
9
10
11
cylinder
Hydraulic unit
Silencer chamber
Hydraulic pump
Electric motor
Buffer chamber
Hydraulic control
valve
Front master
cylinder
Rear brake
caliper
Front brake caliper
Electronic control unit
12 Rear wheel sensor
13 Front wheel sensor
14 ABS warning light
HU components
Components of each system are five parts as follows.
1 Flow control valve
2 Solenoid valve
3 Buffer chamber
4 Hydraulic pump
5 Silencer chamber
Flow control valve 1 works to keep the brake fluid
flow at a constant flow rate while the ABS works.
This valve also increases and decreases the
brake fluid pressure together with the solenoid
valve 2 .
Buffer chamber 3 accumulates the decompressed brake fluid temporarily while the ABS
works.
Hydraulic pump 4 is driven by the motor and it returns the brake fluid which has been stored in the
buffer chamber 3 to the master cylinder side line.
In addition, to increase the quietness, the silencer
chamber 5 is equipped.
6
7
8
9
34
Brake master cylinder
Brake caliper
ABS warning light
ECU
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
OTHER ABS MECHANISM COMPONENTS
ABS warning light
The ABS warning light 1 is designed to inform the
ABS self diagnostic result and located in the meter
panel.
Main switch
ON
Main switch
OFF
“ABS”
warning light
Going on the ABS warning light
1. Turn the main switch on
It goes on for about 2 seconds. It executes the
self diagnosis during this period and goes off.
Goes off
Goes on for
2 seconds.
Goes off
Preparation
2. When the main is turned on and starter switch
is pushed.
Main switch Main switch
OFF
ON
“ABS”
warning
light
Goes
off
NOTE:
Depends on the following requirement
When applying the brake lever
When the engine stop switch is off
When the sidestand is used
Starter switch
Main switch
OFF
ON
Main switch
Starter switch
OFF
ON
Goes on for
2 seconds.
Goes
off
Goes on while the
starter switch is pushed.
Goes
off
Preparation
ABS warning light keeps going on while starter
switch is pashed. The ABS warning light disconnection is confirmed.
NOTE:
Engine oil warning light goes on while the starter
switch is pushed.
3. Light goes on while riding.
Malfunction is detected in the ABS. In this case,
the ABS hydraulic control is not performed and
it becomes the normal braking state.
“ABS”
warning light
Goes on
35
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
4. Flashes while riding.
No problem exists with the ABS function, but it
is estimated that the input has unstable factors.
(For details, refer to the troubleshooting section.)
Goes on
Goes off
NOTE:
The test coupler adapter may be connected with
the test connector.
ABS
warning light
Preparation
5. Test connector
By removing the lower panel of windscreen,
the installed 4 pin connector 1 can be seen.
This is the test connector to call the ABS malfunction code.
When the test coupler adapter 1 is connected
with the test connector, the malfunction history
recorded in the ECU will be displayed by the
ABS warning light flashing.
Test coupler adapter
90890-03149
NOTE:
If the scooter rides with the test coupler adapter
connected, the ABS warning light flashes.
36
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
ABS TROUBLESHOOTING OUTLINE
This section describes the troubleshooting about ABS in details. Read carefully this service manual before
repairing various malfunctions, understand and perform the service.
Electronic control unit (ECU) has the self diagnostic function. When failures occur in the system, the ABS
warning light of meter panel alerts the malfunction.
Trouble shooting mentioned below describes the cause pursuing and service method according to the indication by ABS warning light. For troubleshooting other than these items, perform by following the normal
service method.
WARNING
When the maintenance or check has been performed on related parts to ABS, be sure to execute the
“final check” before delivering the scooter to the customer. Refer to [D-6] FINAL CHECK.
1. ABS warning light goes on and the ABS condition
1) When the ABS warning light keeps going on It works as a normal brake.
Detecting the malfunction by means of the ABS self diagnostic function.
2) Light goes on and off at the time of starting ABS operation is normal.
ABS warning light goes on for 2 seconds every time the main switch is turned on and goes off afterward.
ABS warning lights go on while the starter switch is pushed.
3) When the ABS warning light flashes ABS operation is normal.
Brake switch is defective or improperly adjusted.
Rear wheel is racing.
Continuous riding on extremely uneven roads.
2. Self diagnosis and services
ECU has the self diagnostic function. By utilizing this function, quick and secure services are possible.
Previously occurred error phenomenon can be checked since it also installs the memory for storing malfunction history.
“In case malfunctions are detected”
It is disabled to call the malfunction code by using the ABS warning light since the ABS warning light already
goes on. Connect the test coupler adapter to the test connector, connect a pocket tester to the terminal of
light green lead and check by its pointing needle movement. (Refer to [B-5])
“In case any malfunctions are not detected” It is possible to call the malfunction code by using the ABS warning light. You can check it by using a pocket tester. Note everything if more than two items of malfunction
codes are recorded.
37
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
“Deleting the malfunction code”
When the malfunction service is finished, check the normal operation of scooter then delete the malfunction
code (Refer to [D-6]). By deleting the malfunction code memory, it is possible to pursue the cause correctly if
the next defective phenomenon occurred.
Self diagnosis by ECU
ECU performs the static check for whole system when the main switch is turned on. It is also possible to
check the malfunction while riding. It is possible to check the recorded malfunction data by using a tester
or utilizing the ABS warning light of meter by setting the ECU to the self diagnostic mode since all malfunctions which has been once detected are recorded.
3. Differences between the normal handling and services on a vehicle
Care should be taken not to damage components by shocks and pulling too much since the ABS components are precisely adjusted.
ECU, HU, Wheel sensors and relay boxes are united assemblies.
Malfunction history in ECU is recorded. Delete it when the service is finished. (This is because the past
malfunction contents will be redundantly displayed when the same malfunction occurred again.)
38
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
ABS PARTS LOCATION CHART
Electronic control unit (ECU)
6 ABS warning light
11
Brake light relay
7 Test connector
12
Fail-safe relay
8 Front sensor rotor
13
Front brake hose (Front brake 9 Front wheel sensor
10 Front brake hose (Hydraulic unit- 14
master cylinder-Hydraulic unit)
5 Rear brake hose (Rear brake
15
front brake caliper)
master cylinder-Hydraulic unit)
1
2
3
4
39
Hydraulic unit (HU)
Fuse box
Rear brake hose (Hydraulic unitrear brake caliper)
Rear wheel sensor
Rear sensor rotor
ANTI-LOCK BRAKE SYSTEM (ABS)
ABS CONNECTOR LOCATION CHART
40
CHAS
CHAS
ANTI-LOCK BRAKE SYSTEM (ABS)
ABS CIRCUIT DIAGRAM
3
4
5
8
16
17
Main switch
Battery
Fuse (main)
Fuse (ABS motor)
ECU (electronic control unit)
Front wheel sensor
41
18
19
20
27
28
29
Rear wheel sensor
Fail safe relay
Hydraulic unit
Front brake switch
Brake light relay
Rear brake switch
46
48
60
62
ABS warning light
Speedometer
Start switch
Fuse (ABS)
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
BASIC INSTRUCTION FOR TROUBLESHOOTING
WARNING
Execute the troubleshooting on each malfunction from [A] to [D] in sequence.
Use the sufficiently charged regular batteries only.
[A] Malfunction check by the ABS warning light
[B] Detail check of malfunction
Results by self diagnosis are displayed by the ABS warning light or tester according to the ECU’s operation.
[C]Supposing the malfunction cause and position
Find the malfunction cause by reasoning the place and situation where it occurred.
[D]ABS system services
Execute the final check after disassembly and assembly.
WARNING
Perform the troubleshooting [A][B][C][D] in order. Be sure to follow the order since it results
in the wrong diagnosis if the order is differently taken or omitted.
42
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
BASIC PROCESS FOR TROUBLESHOOTING
It does not go on.
[A]
Check the ABS
warning light.
Flashing
[B-1]
Warning light
does not
go on.
[B-3]
Warning light
keeps flashing.
Goes on for 2 seconds and goes off afterward.
Keeps going on.
[B-5]
Present
malfunction
[B-2]
Warning light
keeps going on.
[B-4]
Past
malfunction
NOTE: Display the
malfunction code
number and record it.
[C-1]
Only ABS
warning light
does not go
on.
Check
the fuse.
[C-2]
All indicator
lights do not
go on.
[C-5]
Diagnoses by
malfunction
codes.
[C-3]
Warning light
keeps flashing.
Check the
connecting parts.
Check the
brake switch
circuit.
Check the
ECU comector.
[C-4]
ABS warning light
flashes every
0.5 second.
Check the
wire harnesses.
To investigate, use
the diagnosis table
(from [C-5-1] to
[C-5-10]).
Check the
test coupler
adaptor.
Explain to the
customer.
Check the
wire harness.
ECU
[D-1]
Sensor
[D-3, 4]
Fail-safe
relay
[D-2]
HU
[D-5]
Check
the piping.
ECU
[D-1]
HU test
[D-6-3]
Are all defective phenomena corrected?
Return to [A]
Delete the malfunction
code record. [D-6-4]
End
NOTE:
Do not delete the malfunction code during the troubleshooting procedures. Be sure to delete it when the
service is finished.
WARNING
Always execute the “final check” when the components related to ABS are checked and serviced.
43
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
ABS TROUBLESHOOTING
[A] MALFUNCTION CHECK BY THE ABS WARNING LIGHT
Turn the main switch on. (Do not start the engine.)
1) Warning light does not go on.
2) Warning light keeps going on.
3) Warning light keeps flashing.
4) Warning light goes on for two seconds and goes off.
[B] DETAIL CHECK OF MALFUNCTION
[B-1] WARNING LIGHT DOES NOT GO ON
Do other indicators operate normally?
1) They work normally.
2) They do not work normally.
[B-2] WARNING LIGHT REMAINS GOING ON
Check the ECU in the taillight unit. Is the coupler securely connected?
1) It is connected.
2) It is disconnected. Securely connect until the “click” sound is heard.
[B-3] WARNING LIGHT KEEPS FLASHING
[B-1]
[B-2]
[B-3]
[B-4]
[C-1]
[C-2]
[B-5]
NOTE:
Check the battery terminal voltage before proceeding to [B-3].
Check the test connector located in the cowling body. Is the T/C terminal connected to the ground?
Grounding (black)
(sky-blue) T / C
Warning light (white/red)
(light green) T / F
1) It is grounded. Disconnect the grounding lead from the T/C terminal and put on the protective cap.
NOTE:
When the test coupler adapter is connected, the T/C terminal is designed to grounded.
[C-3]
2) It is not grounded.
44
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Arrangement and the function of test couplers
ECU becomes the malfunction diagnostic mode when the T/C terminal is grounded.
Malfunction code which the ECU generated in the malfunction diagnostic mode (rise and fall of voltage)
is output at the T/F terminal.
ABS warning light terminal is used when checking the ABS warning light circuit.
To ground the T/C terminal, connect the test coupler adapter with the test connector. Before connecting,
check if the battery is sufficiently charged.
(sky-blue) T / C
(light green) T / F
Grounding (black)
ABS warning light (white/red)
Test coupler adapter
[B-4] MALFUNCTION CHECK BY THE ABS SELF DIAGNOSIS (PAST MALFUNCTION)
Remove the screen and check the location of test connector 1 . Remove the protective cap and connect the
test coupler adapter 2 with the test connector. T/C terminal (sky-blue) is now grounded.
1) ABS warning light flashes every 0.5 second. (longer than 6 seconds)
2) ABS warning light keeps flashing in the pattern as shown below.
As an example, this pattern shows the malfunction code 14.
ABS warning
light go on.
ABS warning
light goes off.
Time (sec.)
45
[C-4]
[C-5]
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[B-5] MALFUNCTION CHECK BY THE ABS SELF DIAGNOSIS (PRESENT MALFUNCTION)
NOTE:
Before proceeding to [B-5], read the part of [B-3] “Arrangement and the function of test coupler”.
Remove the screen and check the location of test connector. Connect the test coupler adapter with the test
connector in order to ground the T/C terminal (sky-blue). (Figure - A )
A
C
Protective cap
Test connector
Lock plate
Grounding
(black)
(white/red)
T/C terminal
T/F terminal
B
Light terminal
(white/red)
(light green)
Test coupler
adapter
(light green)
(white/red)
Set the range of pocket tester to DC20V. Connect the negative (-) terminal of tester to the T/F terminal (light
green) and positive (+) terminal to the positive (+) terminal of battery. (Figure - B )
Read the tester indication. (Figure - C )
As an example, ”10 digits/1 digit pattern” of tester reading is shown below.
This example is the pattern which
shows malfunction code 12.
This example is the pattern which
shows malfunction code 21.
8V
0V
Time
(second)
46
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C] SUPPOSING THE MALFUNCTION CAUSE AND POSITION
[C-1] ONLY ABS WARNING LIGHT DOES NOT GO ON WHEN THE MAIN SWITCH IS TURNED ON
NOTE:
Check following the numbers in sequence.
1. Visual check
1) Check the fuse 1 . (ABS)
Check the cause of fuse blown, repair and replace with a new one.
2) Check the ABS harness and wire harness connector.
Check whether the ABS connector is securely connected with the wire harness. Both harnesses are connected by two connectors. Check both connectors. (Refer to ABS CONNECTOR LOCATION CHART)
3) Check the connection of ECU and ABS harness.
Check whether the ABS harness is securely connected with the ECU. (Refer to ABS CONNECTOR
LOCATION CHART)
2. Confirmation by the test coupler adapter
1) Connect the test coupler and test coupler adapter. (Refer to [B-5])
2) Connect the warning light terminal (white/red) of test coupler adapter to the ground (or the negative (-)
terminal of battery).
If the ABS warning light goes on, the inside of ABS harness may be disconnected.
If the ABS warning light does not goes on, the ABS warning light lead may be disconnected or the warning light’s contact may be defective.
3) Remove the ECU connector (Refer to ABS CONNECTOR LOCATION CHART) and check the continuity
of white/red lead. (ECU and test coupler adapter sides of white/read wire)
If there is a continuity, the ECU is defective. ! Replace the ECU. (Refer to [D-1] MAINTENANCE OF
ECU)
If there is no continuity, the warning light circuit in the ABS harness is defective. Disconnection and others ! Correct (Refer to CIRCUIT DIAGRAM)
47
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C-2] ABS WARNING LIGHT AND ALL OTHER INDICATORS DO NOT GOES ON
NOTE:
Check following the numbers in sequence.
Electric system and the connection of scooter may have caused the problem.
1. Check the power supply system.
1) Is the battery correctly connected?
2) Is the battery voltage normal?
3) Is not the main fuse 1 blown? If it is blown, check the cause, correct and replace.
2.
1)
2)
3)
4)
Check the connection.
Is the main fuse coupler securely connected?
Is the wire harness securely connected with the sub harness?
Is the main switch coupler securely connected?
Is the meter coupler (Refer to ABS CONNECTORS LOCATION CHART) securely connected?
When these checks are finished, return to [A] and check the ABS system again.
[C-3] ABS WARNING LIGHT KEEPS FLASHING
With the engine stopped, check the brake switch (front/rear).
Check if the brake light goes on when the front or rear brake is applied.
1) The light responds only one brake.
The connector of brake switch is detached. (Refer to ABS CIRCUIT DIAGRAM)
The brake switch on the side which the brake light does not respond is defective.
2) The light does not respond to both brakes.
The wire harness may be disconnected or the fuse may be blown. Check the power supply (brown) on
the power source side for the brake switch. (Refer to ABS CIRCUIT DIAGRAM)
3) The brake light goes on.
The ABS harness and wire harness connectors may not be connected. (Refer to ABS CONNECTORS
LOCATION CHART)
48
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C-4] ABS WARNING LIGHT FLASHES EVERY 0.5 SECOND.
This state means that the ECU has not recorded the past malfunction. If the ABS warning light goes on once
in a while but does not record the past malfunction, it is estimated that the ABS warning light went on or
flashed because of failures on other places of scooter. Explain the possible reason enough to the customer
for better understanding.
1. Warning light flashes
Following are probable causes for cases when the ABS warning light flashed while riding, but it recovered to be “normal”, or “the ABS warning light flashed but it stopped flashing when the main switch was
turned off once and turned on again”.
1) While the scooter stood with the centerstand, the rear wheel was rotated. The system is normal.
2) The rear wheel raced. The system is normal.
3) Ran in wheelie. The system is normal.
4) The scooter continuously ridded on the extremely uneven road. The system is normal.
5) The brake switch is defective or improperly adjusted. Replace or adjust.
2. Voltage drop
For the ABS to operate correctly, the voltage should be always higher than the specified voltage. If the
voltage drops lower than 10V, the ABS warning light goes on and stops the ABS operation. When the
voltage recovers to be higher than 10V, the system restarts to operate, but the state which the voltage
dropped lower than 10V means that there are failures with magneto, battery or rectifier/regulator. Correct the failures following regular procedures for normal operation of power supply system.
3. ABS is stopped by ECU
This state occurs because the ECU judged that the system must stop since it was exposed to the environment of extremely strong radio wave, static electricity or radioactivity.
No defectiveness is shown at present. There is no problem about system function. Explain the customer
that the ABS system will operate normally.
49
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C-5] DIAGNOSIS BY THE MALFUNCTION CODE
Malfunction codes explained in [B-4] and [B-5] are used to judge what type of problems have occurred. They
are judged by using the table as follows.
NOTE:
Records all indicated malfunction codes and check the contents for confirmation.
Malfunction code
Problem
Check point
Reference
Front wheel sensor signal does not
come in correctly.
Installation of the front wheel sensor
Front wheel sensor lead, connector
ABS harness circuit
Front sensor housing
[C-5-1] and
the electricity
group
Rear wheel sensor signal does not
come in correctly.
Installation of the rear wheel sensor
Rear wheel sensor lead, connector
ABS harness circuit
Rear sensor housing
[C-5-2] and
the electricity
group
Error signal is detected by the front “13”
or rear “14” wheel sensor.
Installation of sensors
Sensor housings
Sensor rotors
[C-5-3]
No continuity in sensor circuits
Continuity of sensors
ABS harness circuit
Connection of sensor connectors
[C-5-4]
21
Solenoid circuit is disconnected or
short-circuited.
ABS harness circuit
Connector of solenoid
Solenoid
[C-5-5] and
the electricity
group
Disconnection is detected on the
system of fail-safe relay and solenoid.
ABS harness circuit
Fail-safe relay circuit
Connector of solenoid
[C-5-6]
31
32
Defective operation of the fail-safe
relay is detected.
Fail-safe relay
ABS harness circuit
[C-5-7] and
the electricity
group
Defective operation of the motor is
detected.
(Motor stops and will not rotate.)
ABS harness circuit
Connector of motor
Fail-safe relay
HU motor circuit
[C-5-8] and
the electricity
group
Defective operation of the motor is
detected.
(Motor keeps running and will not stop.)
Fail-safe relay
ABS harness circuit
HU motor circuit
[C-5-9] and
the electricity
group
11
*1
12
13 / 14
15 / 16
33
34
50
ANTI-LOCK BRAKE SYSTEM (ABS)
Malfunction
code
Problem
Check point
CHAS
Reference
Brake dragging
HU operation test
(Refer to [D-6-3])
Front wheel brake line
[C-5-10]
41
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 normal)
Brake dragging
HU operation test
(Refer to [D-6-3])
Rear wheel brake line
[C-5-11]
42
Rear 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 normal)
Brake dragging
HU operation test
(Refer to [D-6-3])
Front wheel brake line
Battery voltage
[C-5-12]
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)
Brake dragging
HU operation test
(Refer to [D-6-3])
Rear wheel brake line
Battery voltage
[C-5-13]
52
Rear 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)
Inside of ECU may malfunction.
ABS harness circuit
coupler
(test cou
ler circuits)
ECU (Replace)
[D-1] and
the electricity group
Malfunctioned
at present
resent
[B-5]
(Tester always
indicates 8V.)
*1 Malfunction code “11” is indicated if the rear wheel rotates for longer than about 20 seconds with the front
wheel stopped, or the rear wheel rotates within one second after the main switch is turned on. (In the
case the scooter stands by the centerstand.)
NOTE:
Malfunction code “15” (front wheel sensor), “16” (rear wheel sensor) is indicated when the scooter does not
ride, and the defective connection of either front or rear sensor is detected.
51
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C-5-1] Malfunction code “11” (Front wheel sensor signal does not come in correctly.)
Turn the main switch off once, then turn on again after removing the test coupler adapter.
1) ABS warning light remains going on.
Defective connection in the front wheel sensor circuit.
Sensor connector is detached.
[D-3]
Sensors or leads are disconnected.
[D-3]
ABS harness sensor circuit is disconnected. (Refer to ABS CIRCUIT DIAGRAM)
ECU connector terminal is disconnected.
[D-1]
2) ABS warning light goes on for 2.0 seconds and goes off.
1 With the front wheel stopped, the rear wheel was rotated for longer than about 20 seconds. This is not a
malfunction.
2 Signal is not generated from the front wheel sensor.
Sensor is not in place.
[D-3]
Sensor rotor is defective.
[D-3]
3 Front wheel sensor circuit is short-circuited.
Sensor or leads are short-circuited.
[D-3]
Sensor circuit of ABS harness is short-circuited. (Refer to ABS CIRCUIT DIAGRAM)
4 Front wheel sensor output drops
Sensor signal output may drop due to failures on bearings, wheel axle, wheel and sensor housing of front
wheel. Check if there are looseness, distortion or bending with the assembled condition of these components.
[C-5-2] Malfunction code “12” (Rear sensor signal does not come in correctly.)
Turn the main switch off once, then turn on again.
1) ABS warning light keeps going on.
Defective connection in the rear wheel sensor circuit.
Sensor connector is detached.
[D-4]
Sensors or leads are disconnected.
[D-4]
ABS harness sensor circuit is disconnected. (Refer to ABS CIRCUIT DIAGRAM)
ECU connector terminal is disconnected.
[D-1]
2) ABS warning light goes on for 2.0 seconds and goes off.
1 With the rear wheel stopped, the front wheel was rotated at a speed faster than about 11 km/h. This is
not a malfunction.
2 Signal is not generated from the rear wheel sensor.
Sensor is not in place.
[D-4]
Sensor rotor defective.
[D-4]
3 Rear wheel sensor circuit is short-circuited.
Sensor or leads are short-circuited.
[D-3]
Sensor circuit of ABS harness is short-circuited. (Refer to ABS CIRCUIT DIAGRAM)
52
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
4 Rear wheel sensor output drops
Sensor signal output may drop due to failures on wheel and sensor housing. Check if there are looseness, 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
Check if the wheel sensor is correctly installed with the housing.
[D-3, 4]
Check if there is a looseness between the housings and wheels.
[D-3, 4]
2 Installation of sensor rotors.
Check if the rotors are correctly pressed in the wheels.
[D-3, 4]
Check if foreign materials enter the rotor installing part.
[D-3, 4]
2) Teeth face of sensor rotor may be defective.
Check if there are flaws on the teeth face of rotors.
In this case, check also if there are any foreign materials.
[D-3, 4]
3) Sensor output may be lower.
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.
Sensor connector of the front or rear wheel comes off.
[D-3, 4]
Sensor or leads of the front or rear wheel is disconnected.
[D-3, 4]
Disconnection of the ABS harness sensor circuit. (Refer to ABS CIRCUIT DIAGRAM)
ECU connector terminal of the ABS harness comes off.
[D-1]
NOTE:
There is a possibility that the both sensor lead connectors are disconnected on front and rear wheels.
Check it.
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”.
53
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C-5-5] Malfunction code “21” (Solenoid circuit is disconnected or short-circuited.)
Check the following procedures.
1) Solenoid connector
Check if the solenoid connector terminal is disconnected. (Refer to ABS CONNECTOR LOCATION
CHART)
2) HU solenoid
Check the continuity of solenoid (front or rear wheel)
[D-5]
Check the insulation condition of all solenoid terminals and negative (–) terminal of battery. [D-5]
3) ABS harness
Check the continuity in the solenoid circuit (See the figure below).
Fail-safe
relay
Front
solenoid
red
red
red
Rear
solenoid
ECU
Continuity
between:
1
1
4
5
–
–
–
–
2
3
7
6
white
green
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
Check if the ABS motor fuse beside the battery is blown.
2) Solenoid connector
Check if the solenoid connector located in the side cover at right hand comes off or whether there is insufficient connection. (Refer to ABS CONNECTOR LOCATION CHART)
3) ABS harness
Check the continuity of white/brown leads between the ECU and fail-safe relay. (Refer to ABS CIRCUIT
DIAGRAM)
ECU coupler terminal (white/brown) is disconnected.
[D-1]
Check the continuity of red leads between 1 and 2 , 1 and 3 of solenoid circuit.
Front
solenoid
Fail-safe
relay
red
red
red
Rear
solenoid
4) Fail-safe relay
Check if the fail-safe relay operates correctly.
[D-2]
54
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
5) Wire harness
Check the continuity between the red/blue terminal of fail-safe relay’s coupler and positive (+) terminal of
battery.
Remove the ECU fuse and check the continuity between the brown/white lead of fail-safe relay’s connector and ABS fuse (see the illustration below).
Check the continuity at this point
[C-5-7] Malfunction code “32” (Detected the operation failure of fail-safe relay)
1) Fail-safe relay
Check if the fail-safe relay operates correctly.
[D-2]
2) ABS harness
With the fail-safe relay and ECU removed from the ABS wire harness, check the insulation between the
red/blue and red terminals of the coupler for fail-safe relay.
[C-5-8] Malfunction code “33” (Detected the failure of motor operation (Motor stops and will not
rotate))
1) ABS pump fuse
Check if the fuse for ABS motor beside the batter is blown.
2) Fail-safe relay
Check if the fail-safe relay operates correctly.
[D-2]
3) Wire harness and the ABS harness
Remove the fail-safe relay and check the continuity between the red terminal of ABS harness and ABS
harness side (A terminal as shown in the figure) of ABS fuse terminal in the fuse box. (Remove the fuse
first.) (Refer to ABS CIRCUIT DIAGRAM.)
Terminal B
Terminal A
Check the continuity between the battery positive (+) terminal and battery side of ABS pump fuse terminal (B terminal as shown in the above figure).
Remove the ECU and fail-safe relay from the ABS harness and check the continuity between
white/black lead terminals and between red / white lead terminals.
55
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[C-5-9] Malfunction code “34” (Detected the failure operation of motor (Motor keeps rotating and will
not stop))
1) HU pump motor
Check if the pump motor connector in the left side cover is detached or is insufficiently connected.
Check the continuity of motor.
[D-5]
2) ABS harness
With the HU pump motor connector removed, check the continuity between the black terminal of pump
motor connector of ABS harness and battery negative (–) terminal.
With the ECU connector removed, check the continuity between the red/white terminal of ECU connector and red/white terminal of pump motor connector.
[D-1]
With the fail-safe relay removed, check the continuity between the red/white terminal of pump motor
connector of ABS harness and battery positive (+) terminal.
3) Fail-safe relay
Check if the fail-safe relay operates correctly.
[D-2]
[C-5-10]Malfunction code “41” (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 normal).)
1) Rotation of wheels
Check there is no brake dragging with the front wheel and it rotates smoothly.
Check if there are looseness of bearings, bending of wheel axle or distortion on brake discs.
2) Master cylinder and caliper
Check the brake fluid pressure is correctly transmitted to brake disc when the brake lever is operated and
the pressure is discompressed when the lever is released.
3) Brake fluid
Check the brake fluid in the reservoir tank by observing. (Mixing of water, foreign matters, solidification
and contamination)
Check if air is mixed in the brake hose line.
4) Brake hose line
Check if the brake hose line is folded or broken.
WARNING
Using brake pipes, hoses and union bolts other than genuine YAMAHA parts may close the piping
lines. Do not use them.
Check the connection of brake hose or pipe lines on the master cylinder and caliper sides to the HU are
correct.
WARNING
Front wheel side inlet: Brake hose 1 from the
front master cylinder
Front wheel side outlet: Brake hose 2 from
the front brake caliper
56
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
NOTE:
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 slowly without pulsation.
If the connection of front and rear side is mistaken, when 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
Check if the front and rear solenoid connector terminals (HU and wire harness sides) are reversed.
Terminal color
Solenoid side
Wire harness side
Front
Red, white
Red, white
Rear
Red, green
Red, green
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 by the HU operation
test as described in [D-6].
[C-5-11] Malfunction code “42” (Rear 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 normal.))
1) Rotation of wheels
Check there is no brake dragging with the rear wheel and it rotates smoothly.
Check if there is a distortion on brake discs.
2) Master cylinder and caliper
Check the brake fluid pressure is correctly transmitted to brake disc when the brake lever is operated and
the pressure is discompressed when the lever is released.
3) Brake fluid
Check the brake fluid in the reservoir tank by observing. (Mixing of water, foreign matters, solidification
and contamination)
Check if air is mixed in the brake hose line.
4) Brake hose line
Check if the brake hose line is folded or broken. (Particularly between the HU rear caliper)
WARNING
Using brake pipes, hoses and union bolts other than genuine YAMAHA parts may close the piping
lines. Do not use them.
Check the connection of brake hose or pipe lines on the master cylinder and caliper sides to the HU are
correct.
57
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
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
NOTE:
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 slowly without pulsation.
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
Check if the front and rear solenoid connector terminals (HU and wire harness sides) are reversed.
Terminal color
Solenoid side
Wire harness side
Front
Red, white
Red, white
Rear
Red, green
Red, green
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”
58
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
7) Battery voltage
Measure the battery output voltage.
[C-5-13]Malfunction code “52” (Rear 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-5-11] Malfunction code “42”
2) Master cylinder and caliper
Refer to [C-5-11] Malfunction code “42”
3) Brake fluid
Refer to [C-5-11] Malfunction code “42”
4) Brake hose line
Refer to [C-5-11] Malfunction code “42”
5) Solenoid coupler terminal
Refer to [C-5-11] Malfunction code “42”
6) HU
Refer to [C-5-11] Malfunction code “42”
7) Battery voltage
Refer to [C-5-12] Malfunction code “51”
59
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
ECU AND FAIL SAFE RELAY
Order
Job name/Part name
Q’ty
Remove the parts in order list.
Refer to “TAIL COVER AND FUEL TANK”
in Chapter 3.
ECU and fail safe relay removal
Tail cover
1
2
3
4
5
6
7
Remarks
1
1
2
1
1
1
1
ECU
Cover
Connector
Fail safe relay
Fail safe relay connector
Brake light relay
Brake light relay connector
60
Disconnect the connectors.
Disconnect the connector.
Disconnect the connector.
For installation, reverse the removal
procedure.
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-1] MAINTENANCE FOR ECU
Removing the ECU
1. Remove:
ECU 1
NOTE:
Carefully take out the ECU lead 3 not to damage
the ECU connector and remove the ECU.
2. Remove:
ECU connector 1
ECU connector 2
NOTE:
To remove the ECU coupler, do not pull the ECU
leads.
Always press on the lock 3 and remove it.
Checking the ECU
1. Check:
Terminals 1 of the ECU
Cracks /damages Replace ECU
Terminals 2 of the ECU coupler
Connection defective, contaminated, come-off
Correct or clean.
NOTE:
If the connector is clogged by mud or dirt, clean it
by air blow.
ECU assembly
1. Install:
ECU 1
61
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-2] MAINTENANCE OF THE ABS FAIL-SAFE
RELAY
Removing the fail-safe relay
1. Remove:
ABS fail-safe relay coupler 1
NOTE:
Do not pull the ABS fail-safe relay leads to remove
the ABS fail-safe relay connector.
Always press on the lock 2 and remove it.
Operation of solenoid relay
Checking the fail-safe relay
1. Check:
Solenoid relay continuity
Connect the pocket tester (Ω 1) to terminals.
Check the continuity between the terminal 3
and 4 of solenoid relay.
Tester’s positive (+) lead Terminal 3
Tester’s negative (–) lead Terminal 4
If tester reading is “∞”. Replace the fail-safe
relay.
Check the continuity between the terminal 7
and 8 of solenoid relay.
Tester’s positive (+) lead Terminal 7
Tester’s negative (–) lead Terminal 8
If tester reading is “∞”. Replace the fail-safe
relay.
Finally, connect the battery’s positive (+) terminal to the terminal 7 of solenoid relay, negative (–) terminal to the terminal 8 , and check
the continuity between the solenoid terminal
4 and 5 .
: Continuity
Terminal number
Normal
condition
Connect the
battery to 7
and 8 terminal
62
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Tester’s positive (+) lead Terminal 4
Tester’s negative (–) lead Terminal 5
If tester reading is “∞”. Replace the fail-safe
relay.
Fail-safe relay
Solenoid
relay
Motor
relay
CAUTION:
When connecting the relay and battery terminals, be careful not to short-circuit the battery’s positive (+) and negative (–) terminals.
2. Check:
Continuity of motor relay
Connect the pocket tester (Ω 1) to motor
relay terminals.
First, check the continuity between the motor
relay terminal 1 and 6 .
Tester’s positive (+) lead Terminal 1
Tester’s negative (–) lead Terminal 6
If tester reading is “∞”. Replace the fail-safe
relay.
CAUTION:
Operation of motor relay
If the 1 and 6 of tester leads are connected
reverse, it makes the good or bad detection
impossible. Do not mistake.
: Continuity
Terminal number
Normal
condition
Connect the battery positive (+) terminal to the
terminal 6 , negative (–) terminal to the terminal
1 and check the continuity between motor relay
terminals 2 and 5 .
Tester’s positive (+) lead Terminal 2
Tester’s negative (–) lead Terminal 5
If tester reading is “∞”. Replace the fail-safe
relay.
Connect the
battery to 6
and 1 terminal
CAUTION:
If the connection of positive (+), negative (–)
is mistaken, the diode will be broken. Connect it correctly.
When connecting the battery and relay, be
careful not to short-circuit the battery’s positive (+) and negative (–) terminals.
63
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
FRONT WHEEL SENSOR AND SENSOR ROTOR
70 Nm (7.0 mkg)
23 Nm (2.3 mkg)
Order
1
2
3
4
5
6
7
Job name/Part name
Q’ty
Remarks
Remove the parts in order list.
Front wheel sensor and sensor rotor
removal
Cowling body
Front wheel sensor
Brake caliper
Wheel axle
Front wheel
Sensor housing
Collar
Front wheel sensor lead connector
Refer to “COWLING” in Chapter 3.
1
1
1
1
1
1
1
64
Disconnect the connector.
For installation, reverse the removal
procedure.
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
ABS wheel sensor and the sensor rotor
CAUTION:
Care should be taken to handle the ABS components since they have been accurately adjusted and set, and must be kept away from
shocks and dirt.
ABS wheel sensor cannot be disassembled.
Never disassemble it. If failed, replace with a
new one.
[D-3] MAINTENANCE OF THE FRONT WHEEL
SENSOR AND SENSOR ROTOR
Removing the front wheel sensor
1. Remove:
Clamp 1
NOTE:
Clamp can be easily removed by moving the
clamp tip of brake hose and wheel sensor leads up
and down.
2. Remove:
caliper 1
Wheel sensor 2
CAUTION:
Care should be taken not to allow the sensor
electrode to contact the metal parts when removing the wheel sensor from the wheel hub.
To remove the wheel, do not operate the
brake lever.
Checking the front wheel sensor and the sensor rotor
1. Check:
Front wheel sensor 1
Cracks, bending and distortion Replace
Iron powder and dust Wash
65
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
2. Measure:
S Wheel sensor resistance
Connect the pocket tester (Ω 1) to the terminal of front wheel sensor connector.
Tester’s positive (+) lead Terminal 1
Tester’s negative (–) lead Terminal 2
Regulated resistance:
1.19 to 2.21 kΩ at 20 _C
Out of specification Replace
3. Check:
S Sensor rotor 1
Cracks and damage Replace the wheel assembly
Replacing the wheel sensor rotor
Wheel sensor rotor of YP250A is inserted under
pressure by the special process and cannot be replaced as a single unit. To replace the sensor rotor, replace it as a wheel assembly.
Assembling the front wheel sensor
Proceed in the reverse order of disassembling
paying attention to the following items.
1. Apply:
S Litium soap base grease
1 Wheel axle
66
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
2. Install:
Sensor housing
3. Install:
Front wheel
NOTE:
Align the slot of sensor housing with the projection
part of front fork, then assemble them.
CAUTION:
Install after checking if foreign materials are
mixed in the wheel hub. If foreign materials are
mixed, it causes to damage the inner sensor
rotor and wheel sensor.
5. Install:
Front wheel sensor 1
Brake caliper 2
Clamp 3
23 Nm (2.3 mkg)
35 Nm (3.5 mkg)
NOTE:
When installing the wheel sensor, check if the
wheel sensor lead is twisted or foreign matters attached to the electrode.
CAUTION:
To route the front wheel sensor lead, refer to
the CABLE ROUTING.
67
ANTI-LOCK BRAKE SYSTEM (ABS)
6. Install:
Wheel sensor lead 1
68
CHAS
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
REAR WHEEL SENSOR AND SENSOR ROTOR
23 Nm (2.3 mkg)
Order
1
2
3
Job name/Part name
Q’ty
Remarks
Remove the parts in order list.
Rear wheel sensor and sensor rotor
removal
Tail cover
Rear wheel sensor
Rear wheel sensor lead connector
Rear wheel
1
1
1
Disconnect the connector.
For installation reverse the removal
procedure.
69
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-4] MAINTENANCE OF THE REAR WHEEL
SENSOR AND SENSOR ROTOR
Removing the rear wheel sensor
1. Disconnect:
Wheel sensor lead connector 1
2. Remove:
Clamp 1
3. Remove:
Rear wheel sensor 1
CAUTION:
Care should be taken not to allow the sensor
electrode to contact the metal parts when removing the wheel sensor from the sensor
housing.
Checking the rear wheel sensor and sensor rotor
Refer to Checking the front wheel sensor and sensor rotor.
70
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Replacing the wheel sensor rotor
Wheel sensor rotor of YP250A is pressed in by the
special process and cannot be replaced as a
single unit. To replace the sensor rotor, replace as
a wheel assembly.
Assembling the rear wheel sensor
1. Install:
Rear wheel sensor 1
23 Nm (2.3 mkg)
NOTE:
When installing the wheel sensor, check if the
wheel sensor wire is twisted or foreign materials
attached to the electrode.
CAUTION:
To route the rear wheel sensor lead, refer to the
CABLE ROUTING.
2. Connect:
Wheel sensor lead connector 1
CAUTION:
To route the rear wheel sensor wire, refer to
CABLE ROUTING.
71
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
HYDRAULIC UNIT (HU)
30 Nm (3.0 mkg)
Order
Job name/Part name
Q’ty
Remove the parts in order list.
Refer to “FOOTREST BOARD AND LOWER
COVER” in Chapter 3.
Hydraulic unit removal
Lower cover, footrest board
1
2
3
4
5
6
7
8
9
10
Remarks
Drain the brake fluid.
Union bolt/copper washers
Front brake hose (OUT)
Union bolt/copper washers
Front brake hose (IN)
Union bolt/copper washers
Rear brake hose (OUT)
Union bolt/copper washers
Rear brake hose (IN)
Hydraulic unit
Hydraulic unit lead connector
1/2
1
1/2
1
1/2
1
1/2
1
1
2
72
(HU-Front brake caliper)
(HU-Front master cylinder)
(HU-Rear brake caliper)
(HU-Rear master cylinder)
Disconnect the connectors.
For installation, reverse the removal
procedure.
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-5] MAINTENANCE OF THE HYDRAULIC
UNIT (HU)
CAUTION:
To check the solenoid resistance of hydraulic
unit and continuity of motor, do not remove the
hydraulic unit.
CAUTION:
Care should be taken to handle the ABS components since they have been accurately adjusted and set, and must be kept away from
shocks and dirt.
ABS wheel sensor cannot be disassembled.
Never disassemble it. If failed, replace with a
new one.
Do not turn the main switch on while removing the hydraulic unit.
Do not clean by flowing air.
Do not use the used brake fluid again.
Do not mix the brake fluids of different
brands.
If the brake fluid is attached to the coated surface or plastics, it may cause the damage. Do
not allow it to attach.
If the brake fluid attached the connectors, it
may cause bad contacts. Do not allow it to attach.
If the joint parts related to the hydraulic unit
are removed, be sure to check tightening on
them and bleed air.
73
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Checking 1 the hydraulic unit
(Resistance of solenoid valve/Continuity of
motor)
1. Measure:
S Resistance of solenoid valve (front side)
Connect the pocket tester (Ω 1) to the terminal of solenoid valve (front).
Tester’s positive (+) lead Terminal 1
Tester’s negative (–) lead Terminal 2
Solenoid valve resistance:
Less than 10 Ω at 20 _C
Out of specification Replace the hydraulic
unit
2. Measure:
S Resistance of solenoid valve (rear side)
Connect the pocket tester (Ω 1) to the terminal of solenoid valve (rear).
Tester’s negative (–) lead Terminal 1
Tester’s positive (+) lead Terminal 2
Solenoid valve resistance:
Less than 10 Ω at 20 _C
Out of specification Replace the hydraulic
unit.
3. Check:
S Insulation of solenoid valve
Connect the pocket tester (Ω 1k) to the terminal of solenoid valve and battery negative (–)
terminal.
Tester’s positive (+) lead 1 2 3 4
Tester’s negative (–) lead Battery negative
(–) terminal
If continuity is all right Replace the hydraulic
unit.
4. Check:
S Continuity of the motor (HU)
Connect the pocket tester (Ω 1) to the terminal of motor coupler.
Tester’s positive (+) lead 1 terminal
Tester’s negative (–) lead 2 terminal
Continuity is all right.
No continuity Replace the hydraulic unit.
74
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Removing the hydraulic unit
1. Remove:
Brake hose (Front IN) 1
Brake hose (Front OUT) 2
Brake hose (Rear IN) 3
Brake hose (Rear OUT) 4
NOTE:
Do not operate the brake lever while removing the
brake hose.
CAUTION:
Remove the brake hose after covering the surrounding area of hydraulic unit by using
wastes not to allow the brake fluid to attach
other components.
2. Remove:
Hydraulic unit 1
NOTE:
To avoid the brake fluid leakage and foreign materials mixing, attach the rubber plug a to the union
bolt hole.
Checking 2 the hydraulic unit
1. Check:
Hydraulic unit 1
Cracks and damage Replace the hydraulic
unit
75
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
Installing the hydraulic unit
Proceed in the reverse order of disassembling
paying attention to the following items.
1. Install:
Hydraulic unit 1
NOTE:
Since dusts around the hydraulic unit may enter
the brake fluid in a hose while assembling process, clean up dusts before assembling the brake
hose.
CAUTION:
Do not remove the rubber plug which has been
secured to the hose setting hole of hydraulic
unit while installing the unit.
2. Remove:
Rubber plug
3. Install:
Brake hose
Brake hose
Brake hose
Brake hose
New
1
2
3
4
(from the front master cylinder)
(to the front brake caliper)
(from the rear master cylinder)
(to the rear brake caliper)
Plate washer (Copper washer)
Union bolt
30 Nm (3.0 mkg)
WARNING
Outlet side of front and rear brake hoses are
partially distinguished by means of rubber
hose. Do not mistake to connect them.
76
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
4. Connect:
Solenoid valve lead connector 1
5. Supply:
Reservoir tank
Recommended brake fluid
DOT #4
6. Bleed the air.
7. Check the operation of hydraulic unit according
to the decompression.
Refer to [D-6-3] HU OPERATION TEST2.
CAUTION:
Never forget to check the operation of hydraulic unit according to the decompression.
8. Delete the malfunction code. (Refer to [D-6-4])
9. Trial run. (Refer to [D-6-5])
77
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
AIR BLEEDING (ABS brake system)
WARNING
Always bleed air when the brake related parts
are removed.
CAUTION:
Bleed air following these steps.
a 1st step: Front brake caliper
b 2nd step: Rear brake caliper
Front brake lever 1
Rear brake lever 2
3 Front brake hose (IN)
4 Rear brake hose (IN)
CHECK THE OPERATION OF HYDRAULIC
UNIT ACCORDING TO THE DECOMPRESSION
1. Check the operation by decompression.
Refer to [D-6-3] HU OPERATION TEST2.
[D-6] FINAL CHECK
Checking procedures
1. Check the reservoir tank fluid level
2. Recheck the assembly status of wheel sensors
3. HU operation test
4. Deleting the malfunction codes
5. Trial run
78
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-6-1] CHECKING THE RESERVOIR TANK
FLUID LEVEL
1. Check:
Brake fluid level
Keep the reservoir cap horizontal and check
the level.
Less than the low level Add the brake fluid
more than low level 1 .
Recommended Brake fluid
DOT #4
CAUTION:
Do not mix the brake fluids of different
brands.
If the brake fluid is attached to the coated surface, plastics or rubbers, it may cause the
damage. Do not allow it to attach. Wipe off the
attached brake fluid immediately.
[D-6-2] RECHECKING THE ASSEMBLY STATUS OF WHEEL SENSORS
1. Check if the wheel sensor housing is installed
in place. Refer to [D-3]/[D-4] MAINTENANCE
OF WHEEL SENSORS AND SENSOR ROTORS. (only for the front)
2. Check:
Installation state of wheel sensors 1 to the
sensor housings.
Wheel sensor
23 Nm (2.3 mkg)
79
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-6-3] HU OPERATION TEST 2
WARNING
Be careful to prevent the scooter from falling
down.
1. Move the scooter to the flat place and use the
centerstand.
2. Remove:
Battery case cover
3. Check:
Battery terminal voltage
Battery terminal voltage
Higher than 12.8V.
If it is lower than 12.8V; Charge or replace
the battery.
NOTE:
If the battery terminal voltage is lower than 12.8V,
charge and perform the test.
If the battery terminal voltage is lower than 10V,
the “ABS” warning light goes on and the ECU
stops the operation of ABS.
4. Connect the test coupler adapter 1 to the test
connector 2 . Refer to [B-5].
80
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
5. Turn the main switch to “ON” while operating
the front brake and rear brake levers simultaneously.
NOTE:
When turning the main switch on, it is impossible
to check unless the both front brake and rear
brake levers are operated simultaneously.
Works should be done by two operators.
Main
switch
ON
2.0
seconds
ABS
warning light
6. Check:
HU operation
When the main switch is turned on, the ABS
warning light goes on for 2 seconds and starts
flashing 3 seconds later.
ON
OFF
Flashing
3.0
seconds
0.5
seconds
0.5
seconds
0.5
seconds
0.5
seconds
motor
2.0
3.0
seconds seconds
HU operation
1.5
seconds
At the same time it starts flashing, the front
brake lever 1 will be returned instantaneously. Then, the rear brake lever 2 will be also returned instantaneously.
OFF
CAUTION:
1.0
seconds
0.5
seconds
Ensure that the front brake lever is returned,
then the rear brake in order.
If the order is reversed as the rear brake lever
and front brake lever, recheck the hydraulic
circuit.
If the lever returns slowly not instantaneously, the brake hose may be connected with the
inlet and outlet reversed.
0.5
seconds
When the HU operation is completely correctly,
delete all malfunction codes.
81
ANTI-LOCK BRAKE SYSTEM (ABS)
CHAS
[D-6-4] DELETING THE MALFUNCTION CODE
1. Connect the test coupler adapter 1 to the test
connector 2 . Refer to [B-5].
2. Turn the main switch on.
Previously recorded malfunction code is displayed by the ABS warning light.
3. Turn the engine stop switch 1 off.
CAUTION:
If the starter switch is pushed without turning
the engine stop switch off, it may damage the
starting motor gears or other parts, therefore
be sure to turn it off.
4. Push the starter switch 2 more than 10 times
in 4 seconds, applying the front or rear brake
lever.
NOTE:
ABS warning light goes on when the starter switch
is pushed, but this state is normal.
5. Check that the ABS warning light keeps flashing.
6. Turn the main switch off.
82
ANTI-LOCK BRAKE SYSTEM (ABS)
Main
switch
ON
ABS
warning light
2.0
seconds
7. Turn the main switch on again.
Check that the ABS warning light goes on for 2
seconds, then goes out for 3 seconds and
starts flashing.
8. Turn the main switch off.
ON
OFF
Flashing
3.0
seconds
0.5
seconds
0.5
seconds
CHAS
0.5
seconds
0.5
seconds
9. Disconnect the test coupler adapter from the
test connector, and install the protective cap
with the test coupler adapter. Deleting the malfunction code is now finished.
NOTE:
Do not forget to install the protective cap.
CAUTION:
Since the ECU remains in the memory until the
malfunction code is deleted, always delete the
malfunction code when the service work is finished.
[D-6-5] TRIAL RUN
After all checks and services are completed, always ensure the scooter has no problems by performing the trial running at a speed of faster than
10 km/h.
83
REAR SHOCK ABSORBER AND SWING ARM
CHAS
REAR SHOCK ABSORBER AND SWING ARM
40 Nm (4.0 mkg)
19 Nm (1.9 mkg)
7 Nm (0.7 mkg)
135 Nm (13.5 mkg)
20 Nm (2.0 mkg)
30 Nm (3.0 mkg)
20 Nm (2.0 mkg)
53 Nm (5.3 mkg)
Order
Job name/Part name
Q’ty
Remarks
Remove the parts in order.
Rear shock absorber and swingarm
removal
Side panels
Refer to “COVER AND PANEL” section in
CHAPTER 3.
1
2
3
Box
Nut
Muffler assembly
1
2
1
4
5
6
7
8
9
Axle nut
Rear shock absorber
Swingarm
Collar
Oil seal
Bearing
1
1
1
1
1
1
NOTE:
Loosen.
NOTE:
Remove with the rear brake applied.
Reverse the removal procedure for
installation.
84
1
YP250A ’99 WIRING DIAGRAM
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
COLOR CODE
B . . . . . . . Black
Br . . . . . . Brown
Ch . . . . . . Chocolate
Dg . . . . . . Dark green
G . . . . . . . Green
L . . . . . . . Blue
Lg . . . . . . Light green
O . . . . . . . Orange
65
P .......
R.......
Sb . . . . . .
W ......
Y .......
B/ R . . . . .
Br / L . . . .
Br / W . . . .
Pink
Red
Sky blue
White
Yellow
Black/ Red
Brwon/ Blue
Brown/ White
Br / Y . . . .
G/ R . . . .
G/ Y . . . . .
L/ B . . . . .
L/ G . . . . .
L/ R . . . . .
L/ W . . . .
P/ W . . . .
AC magneto
Rectifier/ Regulator
Main switch
Battery
Fuse (main)
Starter relay
Starter motor
Fuse (ABS motor)
Doide
Terminal
Thermo switch
Auto choke
Ignition unit
Ignition coil
Spark plug
ECU (electronic control unit)
Front wheel sensor
Rear wheel sensor
Fail safe relay
Hydraulic unit
Grip warmer switch (option)
Grip warmer (left) (option)
Grip warmer (right) (option)
Fuse (fan)
Thermo switch (fan)
Fan motor
Front brake switch
Brake light relay
Rear brake switch
Turn signal light (rear)
Tail / brake light
License light
Flasher relay
Horn
Auniliary light
Handlebar switch (left)
Pass switch
Dimmer switch
Horn switch
Turn signal switch
Turn signal light (front)
Headlight
Fuel sender
Thermo unit
Meter assembly
ABS warning light
Clock
Speedometer
Engine temperature gauge
Fuel meter
Oil warning light
Reset switch
Meter light
High beam indicator light
Turn signal indicator light
Seat switch
Box light
Handlebar switch (right)
Engine stop switch
Start switch
Light switch
Fuse (ABS)
Starting circuit cutoff relay
Sidestand switch
ABS test terminal
Brwon/ Yellow
Green/ Red
Green/ Yellow
Blue/ Black
Blue/ Green
Blue/ Red
Blue/ White
Pink/ White
R/ L . . . . .
R/ W . . . .
R/ Y . . . . .
W/G . . . .
W/L . . . .
W/B . . . .
W/R . . . .
Y/ R . . . . .
Red/ Blue
Red/ White
Red/ Yellow
White/ Green
White/ Blue
White/ Black
White/ Red
Yellow/ Red
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