Yamaha YP250A 1999 Supplementary Service Manual Download Page 85

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ANTI-LOCK BRAKE SYSTEM (ABS)

CHAS

CAUTION:

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.

Never forget to check the operation of hydrau-
lic unit according to the decompression.

8. Delete the malfunction code. (Refer to [D-6-4])
9. Trial run. (Refer to [D-6-5])

Summary of Contents for YP250A 1999

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Page 3: ...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 ...

Page 4: ...ve 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 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 Ale...

Page 5: ... 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 e...

Page 6: ...pecifications appearing in the text 10 Possible to maintain with engine mounted 11 Filling fluid 12 Lubricant 13 Special tool 14 Tightening 15 Wear limit clearance 16 Engine speed 17 Ω V A Illustrated symbols 18 to 23 in the exploded dia grams indicate the types of lubricants and lubrica tion points 18 Apply engine oil 19 Apply gear oil 20 Apply molybdenum disulfide oil 21 Apply wheel bearing grea...

Page 7: ...TROL 29 ABS OPERATION AND THE VEHICLE CONTROL 29 ELECTRONICS ABS FEATURE 30 ABS COMPONENTS FUNCTION 31 HYDRAULIC UNIT HU 34 OTHER ABS MECHANISM COMPONENTS 35 ABS TROUBLESHOOTING OUTLINE 37 ABS PARTS LOCATION CHART 39 ABS CONNECTOR LOCATION CHART 40 ABS CIRCUIT DIAGRAM 41 BASIC INSTRUCTION FOR TROUBLESHOOTING 42 BASIC PROCESS FOR TROUBLESHOOTING 43 ABS TROUBLESHOOTING 44 A MALFUNCTION CHECK BY THE ...

Page 8: ...ENSOR ROTOR 64 D 3 MAINTENANCE OF THE FRONT WHEEL SENSOR AND SENSOR ROTOR 65 REAR WHEEL SENSOR AND SENSOR ROTOR 69 D 4 MAINTENANCE OF THE REAR WHEEL SENSOR AND SENSOR ROTOR 70 HYDRAULIC UNIT HU 72 D 5 MAINTENANCE OF THE HYDRAULIC UNIT HU 73 AIR BLEEDING 78 CHECK THE OPERATION OF HYDRAULIC UNIT ACCORDING TO THE DECOMPRESSION 78 D 6 FINAL CHECK 78 D 6 1 CHECKING THE RESERVOIR TANK FLUID LEVEL 79 D 6...

Page 9: ...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 disas sembled 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 ...

Page 10: ...y the front brake lever Reaction force is generated on the front brake lever 0 5 second later and lasts about 2 se conds 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 se conds 8 Turn the main switch off 9 Remove the test coupler adapter from...

Page 11: ... 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 W...

Page 12: ...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 hy draulic unit Hydraulic unit HU Controls the brake fluid pressure of front and rear wheels ac cording to the output signal sent from the electronic control unit Electronic control unit ECU Outputs the operation signal to the hydraulic unit so t...

Page 13: ...s the frequency proportioning to the wheel rotation speed 1 At high speed 2 At low speed 3 Wheel sensor 4 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 func...

Page 14: ...e caliper 9 To the electronic control unit 10 To the front brake caliper 3 Hydraulic unit Hydraulic unit is composed of two pieces of hy draulic control valve solenoid valve flow control valve buffer chamber pump and silencer cham ber 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 u...

Page 15: ...it signals the pressure reduction and the spool 3 of flow control valve is moved to ward to the solenoid valve 3 When the electronic control unit stops the sig nal of pressure reduction the solenoid valve 2 closes and pressurizing starts again Re pressurizing while the ABS works controls the flow of brake fluid by the movement of spool 3 of flow control valve and provides slow pres sure rising 1 O...

Page 16: ...cuit Solenoid motor Solenoid drive circuit Fail safe relay drive circuit Motor relay drive circuit Warning light drive circuit Operation mode switching circuit Fault code output circuit Solenoid valve Motor Hydraulic unit HU Solenoid Motor relay Fail safe relay ABS warning light Checker Speedometer Front wheel speed output circuit 4 Electronic control unit Relation of the input signal and output s...

Page 17: ...mes normal braking Motor relay is also continued by the signal of electronic control unit and starts the motor simultaneously when the ABS pres sure 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 11 Power 12 Fail safe relay 13 Hydraulic unit 1 Solenoid relay 2 Motor relay 3 Solenoid valve 4 El...

Page 18: ...BS 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 thi...

Page 19: ...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 buffe...

Page 20: ...ses 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 cons...

Page 21: ...ps 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 work...

Page 22: ...ly Use only the appropriate special tools as this will help prevent damage caused by the use of inappropri ate tools or improvised techniques When placing an order refer to the list provided below to avoid any mistakes Tool No Tool name Function Illustration 90890 03149 Test coupler adaptor This tool is used to check the ABS diagnosis ...

Page 23: ...e 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 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...

Page 24: ...arker light Tail brake light Flasher light Meter light High beam indicator light Oil indicator light Turn indicator light ABS warning light License light 12 V 60 W 55 W 1 12 V 5 W 1 12 V 5 W 21 W 1 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 ...

Page 25: ...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 CHASSIS Item Standard Limit Rear disc brake Type Disc outside diameter thickness Pad thickness Master cylinder inside diameter Caliper cylinder outside diameter Brake flui...

Page 26: ...l unit ECU 10 Rear wheel sensor 11 Crankcase 12 Over flow hose fuel filler 13 Hydraulic unit 14 Down tube 15 Wireharness 16 Steering head pipe 17 Throttle cable 18 Crankcase breather hose 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 p...

Page 27: ...n K Route the rear wheel sensor lead through the guide L Route the carburetor air ventila tion 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 fill er and hydraulic unit drain hose through the guide O Position the connector of plastic band as illustration P Position the connector of t...

Page 28: ... 10 Reservoir tank hose 11 Starter switch 12 Battery 13 Flasher relay 14 Coolant reservoir tank 15 Crankcase breather hose 16 Air filter case 17 Front brake hose IN 18 Front brake hose OUT 19 Rear brake hose IN 20 Hydraulic unit coupler 21 Rear brake hose OUT 22 Igniter 23 Down tube 24 Wireharness 25 Rear brake hose 26 Battery leads 27 AC magneto lead 28 Starter motor lead 29 Engine ground lead ...

Page 29: ...stic lock ing 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 I Route the seat lock cable through the pipe and align the mark of seat lock cable with the pipe end...

Page 30: ...de Q Fasten the pipe with a steel clamp on the frame R Fasten the fan motor lead side stand switch lead and starter switch lead to the frame with a plastic band S Route the wireharness over the rear brake hose T Route the coolant reservoir tank over flow hose through the guide on the inside of the frame U Fasten the wireharness to the frame with a plastic band V Route the brake hose wirehar ness a...

Page 31: ...or lead 15 Seat lock cable 16 Fuel pump 17 Fuel tank 18 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 C Fasten the sidestand switch lead with a steel clamp on the frame D Route the thermo switch lead out side of the frame E Fasten the wireharness to the frame with a plastic band F Route the battery ...

Page 32: ...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 vacu um hose O Position the end of the clip to out side P Fasten the front wheel sensor and electronic control unit lead to the frame with a plastic band Q Install the fuse box to the stay...

Page 33: ...andlebar upper cover 17 Handlebar 18 Front turn signal light 19 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 C Route the front brake hose through the right hole of the han dlebar under cover D Route the rear brake hose through the left hole of the handlebar under cover E Fasten ...

Page 34: ... 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 ...

Page 35: ...t 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 Howev er the chassis tends to travel forward by its iner tia even though the wheel rotation is lowered The speed of chassis itself is the ch...

Page 36: ...tation of wheels 100 The wheel speed is 0 i e the state of wheel locking 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 slippin...

Page 37: ... wheel ex ceeds 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 exe...

Page 38: ...ndency Accordingly locking of wheels which may occur when the engine brake is applied on the slippery road is beyond the ABS control range Even the ABS equipped scooter cannot pre vent the locking tendency of wheels on the ex tremely 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...

Page 39: ...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 hous ing 2 and to the crankcase for a rear wheel Sensor rotor 3 is pressed in the inn...

Page 40: ...it Warning light drive circuit Operation mode switching circuit Fault code output circuit Solenoid valve Motor Hydraulic unit HU Solenoid Motor relay Fail safe relay ABS warning light Checker Speedometer Front wheel speed output circuit 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 w...

Page 41: ...he ABS control operation performed in ECU is di vided into 2 parts as follows 1 Hydraulic control 2 Self diagnosis These operations will be performed repeating one time in every 8 1000 seconds In the case of fail ure occurrence it is stored in the malfunction code memory allowing easy find and check of failures Depending on the type of failure it will not be re corded in the memory e g battery vol...

Page 42: ...ording to the signal transmitted from the electronic control unit HU components Components of each system are five parts as fol lows 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 wi...

Page 43: ...sult and located in the meter panel 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 2 When the main is turned on and starter switch is pushed Depends on the following requirement When applying the brake lever When the engine stop switch is off When the sidestand is used ABS warning light keeps go...

Page 44: ... be connected with the test connector 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 mal function 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 ...

Page 45: ...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 S...

Page 46: ...g 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 mal functions 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 compo nent...

Page 47: ...ulic unit 5 Rear brake hose Rear brake master cylinder Hydraulic unit 6 ABS warning light 7 Test connector 8 Front sensor rotor 9 Front wheel sensor 10 Front brake hose Hydraulic unit front brake caliper 11 Hydraulic unit HU 12 Fuse box 13 Rear brake hose Hydraulic unit rear brake caliper 14 Rear wheel sensor 15 Rear sensor rotor ABS PARTS LOCATION CHART ...

Page 48: ...40 ANTI LOCK BRAKE SYSTEM ABS CHAS ABS CONNECTOR LOCATION CHART ...

Page 49: ...c control unit 17 Front wheel sensor 18 Rear wheel sensor 19 Fail safe relay 20 Hydraulic unit 27 Front brake switch 28 Brake light relay 29 Rear brake switch 46 ABS warning light 48 Speedometer 60 Start switch 62 Fuse ABS ANTI LOCK BRAKE SYSTEM ABS CHAS ABS CIRCUIT DIAGRAM ...

Page 50: ...function Results by self diagnosis are displayed by the ABS warning light or tester according to the ECU s opera tion 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 Perform the troubleshooting A B C D in order Be sure to follow the order sin...

Page 51: ...fuse Check the connect ing parts Check the brake switch circuit Check the ECU com ector Check the wire har nesses Check the test coupler adaptor ECU D 1 To investigate use the diagnosis table from C 5 1 to C 5 10 Explain to the customer Check the wire harness Sensor D 3 4 Fail safe relay D 2 Check the piping HU test D 6 3 HU D 5 ECU D 1 Are all defective phenomena corrected Return to A Delete the ...

Page 52: ...rs operate normally 1 They work normally C 1 2 They do not work normally C 2 B 2 WARNING LIGHT REMAINS GOING ON Check the ECU in the taillight unit Is the coupler securely connected 1 It is connected B 5 2 It is disconnected Securely connect until the click sound is heard B 3 WARNING LIGHT KEEPS FLASHING Check the battery terminal voltage before proceeding to B 3 Check the test connector located i...

Page 53: ... 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 B 4 MALFUNCTION CHECK BY THE ABS SELF DIAGNOSIS PAST MALFUNCTION Remove the screen and check the location of test connector 1 Remove...

Page 54: ... ABS SELF DIAGNOSIS PRESENT MALFUNCTION 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 Set the range of pocket tester to DC20V Connect the negative terminal of tester to the T F terminal...

Page 55: ...NNECTOR 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 ...

Page 56: ... 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 b...

Page 57: ... 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...

Page 58: ...by the front 13 or rear 14 wheel sensor Installation of sensors Sensor housings Sensor rotors C 5 3 15 16 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 31 Disconnection is detected on the system ...

Page 59: ...operation test Refer to D 6 3 Front wheel brake line Battery voltage C 5 12 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 Brake dragging HU operation test Refer to D 6 3 Rear wheel brake line Battery voltage C 5 13 Malfunctioned at present Inside of ECU may malfunctio...

Page 60: ...o 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 compo nents 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...

Page 61: ...talling 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 ...

Page 62: ...olenoid circuit See the figure below 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 ...

Page 63: ...inals 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 A...

Page 64: ...g 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 ...

Page 65: ...he 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 c...

Page 66: ...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...

Page 67: ...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 volta...

Page 68: ...l safe relay connector Brake light relay Brake light relay connector 1 1 2 1 1 1 1 Remove the parts in order list Refer to TAIL COVER AND FUEL TANK in Chapter 3 Disconnect the connectors Disconnect the connector Disconnect the connector For installation reverse the removal procedure ANTI LOCK BRAKE SYSTEM ABS CHAS ECU AND FAIL SAFE RELAY ...

Page 69: ...2 Remove ECU connector 1 ECU connector 2 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 If the connector is clogged by mud or dirt clean it by air blow ECU assembly 1 Install ECU 1 ...

Page 70: ...ck 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 test...

Page 71: ...tinuity 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 If the 1 and 6 of tester leads are connected reverse it makes the good or bad detection impossible Do not mistake Connect the battery positive terminal to the terminal 6 negative terminal to the terminal 1 and check the continuity bet...

Page 72: ...ake caliper Wheel axle Front wheel Sensor housing Collar Front wheel sensor lead connector 1 1 1 1 1 1 1 Remove the parts in order list Refer to COWLING in Chapter 3 Disconnect the connector For installation reverse the removal procedure 70 Nm 7 0 m kg 23 Nm 2 3 m kg ANTI LOCK BRAKE SYSTEM ABS CHAS FRONT WHEEL SENSOR AND SENSOR ROTOR ...

Page 73: ...HE FRONT WHEEL SENSOR AND SENSOR ROTOR Removing the front wheel sensor 1 Remove Clamp 1 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 Care should be taken not to allow the sensor electrode to contact the metal parts when re moving the wheel sensor from the wheel hub To remove the wheel do not operate the brake...

Page 74: ...specification Replace 3 Check S Sensor rotor 1 Cracks and damage Replace the wheel as sembly Replacing the wheel sensor rotor Wheel sensor rotor of YP250A is inserted under pressure by the special process and cannot be re placed as a single unit To replace the sensor ro tor replace it as a wheel assembly Assembling the front wheel sensor Proceed in the reverse order of disassembling paying attenti...

Page 75: ... assemble them 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 When installing the wheel sensor check if the wheel sensor lead is twisted or foreign matters at tached to the electrode To route the front wheel sensor lead refer to t...

Page 76: ...68 ANTI LOCK BRAKE SYSTEM ABS CHAS 6 Install Wheel sensor lead 1 ...

Page 77: ...rotor removal Tail cover Rear wheel sensor Rear wheel sensor lead connector Rear wheel 1 1 1 Remove the parts in order list Disconnect the connector For installation reverse the removal procedure 23 Nm 2 3 m kg ANTI LOCK BRAKE SYSTEM ABS CHAS REAR WHEEL SENSOR AND SENSOR ROTOR ...

Page 78: ...1 Disconnect Wheel sensor lead connector 1 2 Remove Clamp 1 3 Remove Rear wheel sensor 1 Care should be taken not to allow the sensor electrode to contact the metal parts when re moving the wheel sensor from the sensor housing Checking the rear wheel sensor and sensor ro tor Refer to Checking the front wheel sensor and sen sor rotor ...

Page 79: ...unit To replace the sensor rotor replace as a wheel assembly Assembling the rear wheel sensor 1 Install Rear wheel sensor 1 When installing the wheel sensor check if the wheel sensor wire is twisted or foreign materials attached to the electrode To route the rear wheel sensor lead refer to the CABLE ROUTING 2 Connect Wheel sensor lead connector 1 To route the rear wheel sensor wire refer to CABLE ...

Page 80: ... 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 Remove the parts in order list Refer to FOOTREST BOARD AND LOWER COVER in Chapter 3 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 30 Nm 3 0 ...

Page 81: ...e disassembled Never disassemble it If failed replace with a new one Do not turn the main switch on while remov ing 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 sur face or plastics it may cause the damage Do not allow it to attach If the brake fluid attached the con...

Page 82: ...t tester Ω 1 to the termi nal 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 ter minal of solenoid valve and battery negative terminal Tester s positive lead 1 2 3 4 Tester s negati...

Page 83: ...ile removing the brake hose Remove the brake hose after covering the sur rounding area of hydraulic unit by using wastes not to allow the brake fluid to attach other components 2 Remove Hydraulic unit 1 To avoid the brake fluid leakage and foreign mate rials 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 h...

Page 84: ...o cess clean up dusts before assembling the brake hose 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 1 from the front master cylinder Brake hose 2 to the front brake caliper Brake hose 3 from the rear master cylinder Brake hose 4 to the rear brake caliper Union bolt 30 Nm 3 0 m kg ...

Page 85: ... 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 Never forget to check the operation of hydrau lic unit according to the decompression 8 Delete the malfunction code Refer to D 6 4 9 Trial run Refer to D 6 5 ...

Page 86: ...ake 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 malfunc...

Page 87: ...luids of different brands If the brake fluid is attached to the coated sur face 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 STA TUS 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 RO TORS only for the front 2 Check...

Page 88: ...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 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 Re...

Page 89: ...ly Works should be done by two operators 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 At the same time it starts flashing the front brake lever 1 will be returned instantaneous ly Then the rear brake lever 2 will be also re turned instantaneously Ensure that the front brake lever is returned then the rear bra...

Page 90: ... 3 Turn the engine stop switch 1 off 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 ABS warning light goes on when the starter switch is pushed but this state is normal 5 Check that the ...

Page 91: ... off 9 Disconnect the test coupler adapter from the test connector and install the protective cap with the test coupler adapter Deleting the mal function code is now finished Do not forget to install the protective cap Since the ECU remains in the memory until the malfunction code is deleted always delete the malfunction code when the service work is fin ished D 6 5 TRIAL RUN After all checks and ...

Page 92: ...shock absorber Swingarm Collar Oil seal Bearing 1 2 1 1 1 1 1 1 1 Remove the parts in order Refer to COVER AND PANEL section in CHAPTER 3 Loosen Remove with the rear brake applied Reverse the removal procedure for installation NOTE NOTE 40 Nm 4 0 m kg 19 Nm 1 9 m kg 135 Nm 13 5 m kg 7 Nm 0 7 m kg 20 Nm 2 0 m kg 30 Nm 3 0 m kg 20 Nm 2 0 m kg 53 Nm 5 3 m kg REAR SHOCK ABSORBER AND SWING ARM ...

Page 93: ...fe relay 20 Hydraulic unit 21 Grip warmer switch option 22 Grip warmer left option 23 Grip warmer right option 24 Fuse fan 25 Thermo switch fan 26 Fan motor 27 Front brake switch 28 Brake light relay 29 Rear brake switch 30 Turn signal light rear 31 Tail brake light 32 License light 33 Flasher relay 34 Horn 35 Auniliary light 36 Handlebar switch left 37 Pass switch 38 Dimmer switch 39 Horn switch ...

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Summary of Contents for YP250A 1999

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Yamaha YP250A 1999, Supplementary Service Manual, Page: 85 / 93

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Summary of Contents for YP250A 1999

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