ad blue YAMAHA WR 250F 2017 User Guide

FUEL INJECTION SYSTEM
9-40
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between throttle position
sensor coupler and ECU cou-
pler.
black/blue–black/blue
yellow–yellow
blue–bluePush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Installed condition of throttle
position sensor.
Check for looseness or
pinching.Improperly installed sensor
 Reinstall or replace the
sensor.
Refer to “ADJUSTING THE
THROTTLE POSITION SEN-
SOR” on page 8-11.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Applied voltage of throttle po-
sition sensor lead.Check the applied voltage.
(black/blue–blue)
Refer to “CHECKING THE
THROTTLE POSITION SEN-
SOR” on page 9-79.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 6.
Location of discon-
nected leadOutput
voltage
Disconnected
ground lead5 V
Disconnected out-
put lead0 V
Disconnected
power supply lead0 V
6 Defective throttle position
sensor.Check throttle position sen-
sor signal.
Execute the diagnostic mode.
(Code No. 01)
When the throttle valve is fully
closed:
A value of 11–14 is indicated.
When throttle valve is fully
open:
A value of 109–116 is indicat-
ed.
An indicated value is out of
the specified range.  Re-
place the throttle position
sensor.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 7. Fault code No. 15
Item Throttle position sensor: open or short circuit detected.

FUEL INJECTION SYSTEM
9-42
TIP
• Make sure that the engine is completely cool before checking the coolant temperature sensor.
• Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. 21
Item Coolant temperature sensor: open or short circuit detected.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.06
Diagnostic tool displayDisplays the coolant temperature.
ProcedureCompare the actually measured coolant temperature with the
Yamaha diagnostic tool display value.
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of coolant tem-
perature sensor coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between coolant temperature
sensor coupler and ECU cou-
pler.
green/white–green/white
black/blue–black/bluePush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Installed condition of coolant
temperature sensor.
Check for looseness or
pinching.Improperly installed sensor
 Reinstall or replace the
sensor.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.

FUEL INJECTION SYSTEM
9-44
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay. 3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between intake air tempera-
ture sensor coupler and ECU
coupler.
black/blue–black/blue
brown/white–brown/whitePush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Installed condition of intake
air temperature sensor.
Check for looseness or
pinching.Improperly installed sensor
 Reinstall or replace the
sensor.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Defective intake air tempera-
ture sensor.Execute the diagnostic mode.
(Code No. 05)
When engine is cold:
Displayed temperature is
close to the ambient temper-
ature.
The displayed temperature is
not close to the ambient tem-
perature.  Check the intake
air temperature sensor.
Replace if defective.
Refer to “CHECKING THE
INTAKE AIR TEMPERA-
TURE SENSOR” on page 9-
80.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 6.
6 Malfunction in ECU. Replace the ECU.
Fault code No. 30
Item Latch up detected.
Fail-safe systemUnable to start engine
Unable to drive vehicle
Diagnostic code No.08
Diagnostic tool displayLean angle sensor output voltage
• 0.4–1.4 (upright)
• 3.7–4.4 (overturned)
ProcedureRemove the lean angle sensor and incline it more than 45 degrees.
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 The vehicle has overturned. Raise the vehicle upright. Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2. Fault code No. 22
Item Intake air temperature sensor: open or short circuit detected.

FUEL INJECTION SYSTEM
9-47
TIP
Disconnect the fuel pump coupler when this diagnostic tool is used.
Fault code No. 39
Item Injector: open or short circuit detected.
Fail-safe systemUnable to start engine
Unable to drive vehicle
Diagnostic code No.36
ActuationActuates injector five times at one-second intervals.
The engine trouble warning light and the “WARNING” on the
Yamaha diagnostic tool screen come on each time the injector is
actuated.
ProcedureCheck that injector is actuated five times by listening for the oper-
ating sound.
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of injector cou-
pler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 2.
Operating sound  Go to
item 6.
2 Defective injector. Measure the fuel injector re-
sistance.
Replace if out of specifica-
tion.
Refer to “CHECKING THE
FUEL INJECTOR” on page 9-
81.Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 3.
Operating sound  Go to
item 6.
3 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Execute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 4.
Operating sound  Go to
item 6.
4 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between injector coupler and
ECU coupler.
red/black–red/black
red–red/blueExecute the diagnostic mode
(Code No. 36).
No operating sound  Go to
item 5.
Operating sound  Go to
item 6.
5 Malfunction in ECU. Replace the ECU. —
6 Delete the fault code. — Start the engine and let it idle
for approximately 5 seconds.
Check that the fault code
number is not displayed.

FUEL INJECTION SYSTEM
9-48
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. 41
Item Lean angle sensor: open or short circuit detected.
Fail-safe systemUnable to start engine
Able to drive vehicle
Diagnostic code No.08
Diagnostic tool displayLean angle sensor output voltage
• 0.4–1.4 (upright)
• 3.7–4.4 (overturned)
ProcedureRemove the lean angle sensor and incline it more than 45 degrees.
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of lean angle
sensor coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between lean angle sensor
coupler and ECU coupler.
blue–blue
yellow/green–yellow/green
black/blue–black/bluePush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Defective lean angle sensor. Execute the diagnostic mode.
(Code No. 08)
Replace if defective.
Refer to “CHECKING THE
LEAN ANGLE SENSOR” on
page 9-75.Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Malfunction in ECU. Replace the ECU.

FUEL INJECTION SYSTEM
9-49
Fault code No. 43
ItemFuel system voltage: incorrect voltage supplied to the fuel in-
jector and fuel pump.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.09
Diagnostic tool displayFuel system voltage
Approximately 12.0 (V)
ProcedureDisconnect the main relay, and push the start switch or push down
the kickstarter lever.
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of main relay
coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between battery terminal and
ECU coupler.
red-red
red-red/white
Between main relay coupler
and ECU coupler.
brown-brown
blue/red-blue/redStart the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Defective main relay. No operating sound  Re-
place the main relay.Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Defective main relay. Execute the diagnostic mode.
(Code No. 09)
Fuel system voltage is below
3 V  Replace the main re-
lay.Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 6.
6 Malfunction in ECU. Replace the ECU.

ELECTRICAL COMPONENTS
9-73
Radiator fan motor relay
EAS2GBB387CHECKING THE DIODE
1. Check:
•Diode
Out of specification  Replace.
TIP
The pocket tester and the analog pocket tester
readings are shown in the following table.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Disconnect the diode from the wire harness.b. Connect the pocket tester ( 1) to the di-
ode coupler as shown.
c. Check the diode for continuity.
d. Check the diode for no continuity.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB388CHECKING THE IGNITION SPARK GAP
1. Check:
• Ignition spark gap
Out of specification  Perform the ignition
system troubleshooting, starting with step 4.
Refer to “TROUBLESHOOTING” on page 9-
4.
TIP
If the ignition spark gap is within specification,
the ignition system circuit is operating normally.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the spark plug cap from the spark
plug.
b. Connect the ignition checker “1” as shown.
c. Push the engine stop switch.
d. Measure the ignition spark gap “a”.
1. Positive battery terminal
2. Negative battery terminal
3. Positive tester probe
4. Negative tester probe
Result
Continuity
(between “3” to “4”)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
No continuity
Tester positive lead  Sky blue
“1”
Tester negative lead  Green/
Black “2”
Continuity
Tester positive lead  Green/
Black “2”
Tester negative lead  Sky blue
“1”
No continuity
Tester positive lead  Red “3”
Tester negative lead  Red/Blue
“4”
Continuity
Tester positive lead  Red/Blue
“4”
Tester negative lead  Red “3”
1 23
4
P/L
R/L
R/W
Br,R/W
Minimum ignition spark gap
6.0 mm (0.24 in)
Ignition checker
90890-06754
Oppama pet–4000 spark checker
YM-34487
2. Spark plug cap
2
1
4
3
R Sb
G/B R/L

ELECTRICAL COMPONENTS
9-75
EAS2GBB391CHECKING THE CRANKSHAFT POSITION
SENSOR
1. Disconnect:
• Crankshaft position sensor coupler
(from the wire harness)
2. Check:
• Crankshaft position sensor resistance
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 100) to the
crankshaft position sensor coupler.
b. Measure the crankshaft position sensor re-
sistance.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB392CHECKING THE LEAN ANGLE SENSOR
1. Remove:
• Lean angle sensor
(from the bracket)
2. Check:
• Lean angle sensor output voltage
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the lean angle sensor coupler to
the wire harness.
b. Connect the pocket tester (DC 20 V) to the
lean angle sensor coupler as shown.
c. Incline the lean angle sensor.
d. Measure the lean angle sensor output volt-
age.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB393
Crankshaft position sensor resis-
tance
228–342 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Gray “1”
• Negative tester probe 
Black “2”
12
Gy B
Lean angle sensor output voltage
Operating angle
45 °
Output voltage up to operating
angle
0.4–1.4 V
Output voltage over operating an-
gle
3.7–4.4 V
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Test harness– lean angle sensor
(6P)
90890-03209
Test harness– lean angle sensor
(6P)
YU-03209
• Positive tester probe 
Yellow/Green “1”
• Negative tester probe 
Black/Blue “2”
2 1
Ã45 Ã
45

ELECTRICAL COMPONENTS
9-78
EAS2GBB397CHECKING THE RESISTER
1. Disconnect:
• Resister coupler
(from the wire harness)
2. Check:
• Resister resistance
Out of specification  Replace the resister.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 10) to the re-
sister as shown.
b. Measure the resistance of the resister.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB398CHECKING THE RADIATOR FAN MOTOR
1. Check:
• Radiator fan motor
Faulty/rough movement  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Disconnect the radiator fan motor coupler
from the wire harness.
b. Connect the battery (DC 12 V) as shown.c. Measure the radiator fan motor movement.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB399CHECKING THE COOLANT TEMPERATURE
SENSOR
1. Remove:
• Coolant temperature sensor
EWA
WARNING
• Handle the coolant temperature sensor
with special care.
• Never subject the coolant temperature
sensor to strong shocks. If the coolant
temperature sensor is dropped, replace it.
2. Check:
• Coolant temperature sensor resistance
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 1k/100) to
the coolant temperature sensor. Resister resistance
64.6–71.4 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Black “1”
• Negative tester probe 
Black “2”
• Positive battery terminal 
Blue “1”
• Negative battery terminal 
Black “2”
1
2
Coolant temperature sensor re-
sistance
2512–2777  at 20 °C (2512–
2777  at 68 °F)
210–220  at 100 °C (210–220 
at 212 °F)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Green/White “1”
• Negative tester probe 
Black/Blue “2”
12
12V
LB

ELECTRICAL COMPONENTS
9-79
b. Immerse the coolant temperature sensor in
a container filled with coolant.
TIP
Make sure the coolant temperature sensor ter-
minals do not get wet.
c. Place a thermometer in the coolant.
d. Slowly heat the coolant, and then let it cool
to the specified temperature indicated in the
table.
e. Check the coolant temperature sensor for
continuity at the temperatures indicated in
the table.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB400CHECKING THE THROTTLE POSITION
SENSOR
1. Remove:
• Throttle position sensor
(from the throttle body)
EWA
WARNING
• Handle the throttle position sensor with
special care.
• Never subject the throttle position sensor
to strong shocks. If the throttle position
sensor is dropped, replace it.
2. Check:
• Throttle position sensor maximum resis-
tance
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 1k) to the
throttle position sensor.
b. Check the throttle position sensor maximum
resistance.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
3. Install:
• Throttle position sensor
TIP
When mounting the throttle position sensor, ad-
just its angle properly. Refer to “ADJUSTING
THE THROTTLE POSITION SENSOR” on
page 8-11.
12
G/W B/L
B/L G/W
Resistance
6.30 k
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Blue “1”
• Negative tester probe 
Black/Blue “2”
21