2015 YAMAHA WR 250F ignition

IGNITION SYSTEM
9-3
1. Joint connector
2. Joint connector
4. AC magneto
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
23.Ignition coil
24.Spark plug
30.Joint connector
35.Lean angle sensor
36.Engine stop switch
48.Frame ground

IGNITION SYSTEM
9-4
EAS2GB2361TROUBLESHOOTING
The ignition system fails to operate (no spark or intermittent spark).
TIP
Before troubleshooting, remove the following part (s):
1. Seat
2. Side cover (left/right)
3. Air scoop (left/right)
4. Fuel tank
5. Fuel tank
1. Check the fuse.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Replace the fuse(s).
OK 
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 9-69.NG 
• Clean the battery terminals.
• Recharge or replace the battery.
OK 
3. Check the spark plug.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Re-gap or replace the spark plug.
OK 
4. Check the ignition spark gap.
Refer to “CHECKING THE IGNI-
TION SPARK GAP” on page 9-73.OK 
The ignition system is normal.
NG 
5. Check the ignition coil.
Refer to “CHECKING THE IGNI-
TION COIL” on page 9-74.NG 
Replace the ignition coil.
OK 
6. Check the crankshaft position sen-
sor.
Refer to “CHECKING THE CRANK-
SHAFT POSITION SENSOR” on
page 9-74.NG 
Replace the stator assembly.
OK 
7. Check the engine stop switch.
Refer to “CHECKING THE
SWITCHES” on page 9-64.NG 
Replace the engine stop switch.
OK 

IGNITION SYSTEM
9-5
8. Check the lean angle sensor.
Refer to “CHECKING THE LEAN
ANGLE SENSOR” on page 9-75.NG 
Replace the lean angle sensor.
OK 
9. Check the entire ignition system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-2.NG 
Properly connect or repair the ignition sys-
tem’s wiring.
OK 
Replace the ECU.

FUEL INJECTION SYSTEM
9-30
EAS2GB2376ECU SELF-DIAGNOSTIC FUNCTION
The ECU is equipped with a self-diagnostic function in order to ensure that the fuel injection system
is operating normally. If this function detects a malfunction in the system, it immediately operates the
engine under substitute characteristics and illuminates the engine trouble warning light to alert the
rider that a malfunction has occurred in the system. Once a malfunction has been detected, a fault
code number is stored in the memory of the ECU.
• To inform the rider that the fuel injection system is not functioning, the engine trouble warning light
flashes while the start switch is being pushed to start the engine.
• If a malfunction is detected in the system by the self-diagnostic function, the ECU provides an ap-
propriate substitute characteristic operation, and alerts the rider of the detected malfunction by illu-
minating the engine trouble warning light.
Engine trouble warning light indication and fuel injection system operation
* The warning light flashes when any one of the following conditions is present and the start switch
is pushed:
Checking the engine trouble warning light
The engine trouble warning light comes on for around 2 seconds when pushing the start switch to
turn on the meter light and the engine trouble warning light comes on while the start switch is being
pushed.Warning light indica-
tionECU operationFuel injection opera-
tionVehicle operation
Flashing* Warning provided
when unable to start
engineOperation stopped Cannot be operated
Remains on Malfunction detected Operated with substi-
tute characteristics in
accordance with the
description of the mal-
functionCan or cannot be oper-
ated depending on the
fault code
12: Crankshaft position sensor 41: Lean angle sensor
(open or short circuit)
30: Lean angle sensor
(latch up detected)50: ECU internal malfunction
(faulty ECU memory)
33: Ignition coil
(Malfunction detected in the primary wire
of the ignition coil)
a. The meter light does not come on.
b. The meter light comes on.
c. Light OFF
d. Light ON for 2 seconds
ab
c cd

FUEL INJECTION SYSTEM
9-31
ECU detects an abnormal signal from a sensor
If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illu-
minates the engine trouble warning light and provides the engine with alternate operating instructions
that are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are
programmed for each sensor in order to provide the engine with alternate operating instructions that
enable the engine to continue operating or stop operating, depending on the conditions.
EAS2GB2377TROUBLESHOOTING METHOD
The engine operation is not normal and the engine trouble warning light comes on.
1. Check:
• Fault code number
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a. Connect the Yamaha diagnostic tool. Refer to “YAMAHA DIAGNOSTIC TOOL” on page 9-32.
b. Check the fault code number displayed on the Yamaha diagnostic tool.
c. Identify the faulty system with the fault code number.
d. Identify the probable cause of the malfunction.
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2. Check and repair the probable cause of the malfunction.
3. Perform the reinstatement action for the fuel injection system. Refer to “Confirmation of service
completion” in the appropriate table in “TROUBLESHOOTING DETAILS” on page 9-35.
4. After pushing the engine stop switch, push the start switch to check whether the fault code no. is
displayed.
TIP
If another fault code number is displayed, repeat steps (1) to (4) until no fault code number is dis-
played.
5. Erase the malfunction history in the diagnostic mode. Refer to “SENSOR OPERATION TABLE”
(Diagnostic code No.62).
TIP
Turning off the meter light will not erase the malfunction history.
The engine operation is not normal, but the engine trouble warning light does not come on.
1. Check the operation of the following sensors and actuators in the diagnostic mode. Refer to
“TROUBLESHOOTING DETAILS” on page 9-35.
If a malfunction is detected in the sensors or actuators, repair or replace all faulty parts.
If no malfunction is detected in the sensors and actuators, check and repair the inner parts of the
engine.Fault code No. No fault code No.
Check and repair. Refer to “TROUBLESHOOT-
ING DETAILS” on page 9-35.
Monitor the operation of the sensors and actua-
tors in the diagnostic mode. Refer to “TROU-
BLESHOOTING DETAILS” on page 9-35 and
“LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE
ACTIONS” on page 10-5.Check and repair.
01: Throttle position sensor signal (throttle angle)
30: Ignition coil
36: Injector

FUEL INJECTION SYSTEM
9-32
EAS2GB2378YAMAHA DIAGNOSTIC TOOL
This model uses the Yamaha diagnostic tool to identify malfunctions.
For information about using the Yamaha diagnostic tool, refer to the operation manual that is included
with the tool.
FEATURES OF THE YAMAHA DIAGNOSTIC TOOL
A diagnosis can be made more quickly than traditional methods with the Yamaha diagnostic tool.
Using this software, ECU and sensor data, as well as fault diagnosis, vehicle maintenance, and any
necessary information can be recorded and displayed on your computer screen through a USB
adapter connected to the computer interface with a communication cable connected to the vehicle’s
ECU.
Data obtained in various functions can be saved as vehicle history, and can be accumulated.
FUNCTIONS OF THE YAMAHA DIAGNOSTIC TOOL
However, the diagnostic tool cannot be used to freely change the basic vehicle functions, such as
adjusting the ignition timing.
CONNECTING THE YAMAHA DIAGNOSTIC TOOL
1. Remove the coupler for connecting setting tool.Yamaha diagnostic tool
90890-03231
Yamaha diagnostic tool (US)
90890-03234
Fault diagnosis mode Fault codes recorded on the ECU are read, and the con-
tents are displayed.
Function diagnostic mode Check the operation of the output value of each sensor
and actuator.
Inspection mode Determine whether each sensor or actuator is functioning
properly.
CO adjustment mode Adjust the concentration of CO admissions during idling.
Monitoring mode Displays a graph of sensor output values for actual oper-
ating conditions.
Logging mode Records and saves the sensor output value in actual driv-
ing conditions.
View log Displays the logging data.
ECU rewrite If necessary, the ECU is rewritten using the ECU rewrite
data provided by Yamaha. Ignition timing adjustment, etc.
cannot be changed from the vehicle’s original state.

FUEL INJECTION SYSTEM
9-45
2 Installed condition of lean an-
gle sensor.Check the installed direction
and condition of 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 3.
3 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 4.
4 Malfunction in ECU. Replace the ECU.
Fault code No. 33
ItemIgnition coil: open or short circuit detected in the primary lead
of the ignition coil.
Fail-safe systemUnable to start engine
Unable to drive vehicle
Diagnostic code No.30
ActuationActuates the ignition coil 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 ignition coil
is actuated.
ProcedureCheck that a spark is generated five times.
• Connect an ignition checker.
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of ignition coil
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. Fault code No. 30
Item Latch up detected.

FUEL INJECTION SYSTEM
9-46
3 Connection of sub wire har-
ness coupler.Check the lock-
ing condition of the
coupler.Disconnect the cou-
pler and check the pins (bent
or broken terminals and lock-
ing condition of the pins).Improperly connected 
Connect the coupler secure-
lyor repair/replace the sub
wire harness.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 4.
4 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
Between ignition coil coupler
and ECU coupler.
orange–orangeStart 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 Installed condition of ignition
coil.
Check for looseness or
pinching.Improperly installed sensor
 Reinstall or replace the
sensor.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 Defective ignition coil. (test
the primary coils for continu-
ity)Check the ignition coil.
Replace if defective.
Refer to “CHECKING THE
IGNITION COIL” on page 9-
74.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 7.
7 Malfunction in ECU. Execute the diagnostic mode
(diagnostic code No. 30).
No spark  Replace the
ECU. Fault code No. 33
ItemIgnition coil: open or short circuit detected in the primary lead
of the ignition coil.