2015 YAMAHA WR 250F check engine light

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
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
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.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
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
9-35
6. Condition
The current conditions are displayed. (Detected/Recovered)
7. Symptom
The symptoms of the detected malfunction are displayed.
8. Diagnosis code
The diagnosis codes related to the detected malfunction are displayed.
9. FFD (only for models that can display freeze frame data)
The mark “ ” is displayed when the freeze frame data is available.
10.ECU conduction time (hour: minute: second)
The total ECU conduction time (total hours the vehicle's main switch was ON) when the malfunc-
tion was detected is displayed.
11.Number of main switch operation after detection
The number of times the meter light comes on by pushing the start switch between the malfunction
detection and code reading is displayed.
12.Number of occurrences
The number of malfunction occurrences between the malfunction detection and code reading is
displayed.
EAS2GB2379TROUBLESHOOTING DETAILS
This section describes the measures per fault code number displayed on the diagnostic tool. Check
and service the items or components that are the probable cause of the malfunction following the or-
der given.
After the check and service of the malfunctioning part have been completed, reset the diagnostic tool
display according to the reinstatement method.
Fault code No.:
Fault code number displayed on the diagnostic tool when the engine failed to work normally.
Diagnostic code No.:
Diagnostic code number to be used when the diagnostic mode is operated.
Fault code No. 12
ItemCrankshaft position sensor: no normal signals are received
from the crankshaft position sensor.
Fail-safe systemUnable to start engine
Unable to drive vehicle
Diagnostic code No.—
Diagnostic tool display—
Procedure—
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of crankshaft po-
sition 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.Crank the engine.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.

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
9-47
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
9-53
TIP
Before troubleshooting, disconnect the starter motor lead from the starter motor. 3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
light green–light greenPush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Yamaha diagnostic tool mal-
function.Replace the Yamaha diag-
nostic tool.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.
Fault code No. Er-2
ItemSignals from the ECU cannot be received within the specified
period of time.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.—
Diagnostic tool display—
Procedure—
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of Yamaha diag-
nostic tool 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.
light green–light greenPush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4. Fault code No. waiting for connection
Item No communication signal is received from the ECU.

FUEL INJECTION SYSTEM
9-54
TIP
Before troubleshooting, disconnect the starter motor lead from the starter motor. 4 Yamaha diagnostic tool mal-
function.Replace the Yamaha diag-
nostic tool.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.
Fault code No. Er-3
Item Data from the ECU cannot be received correctly.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.—
Diagnostic tool display—
Procedure—
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of Yamaha diag-
nostic tool 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.
light green–light greenPush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Yamaha diagnostic tool mal-
function.Replace the Yamaha diag-
nostic tool.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. Fault code No. Er-2
ItemSignals from the ECU cannot be received within the specified
period of time.

FUEL INJECTION SYSTEM
9-55
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. Er-4
ItemRegistered data cannot be received from the Yamaha diagnos-
tic tool.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.—
Diagnostic tool display—
Procedure—
ItemProbable cause of malfunc-
tion and checkMaintenance jobConfirmation of service
completion
1 Connection of Yamaha diag-
nostic tool 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.
light green–light greenPush the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Yamaha diagnostic tool mal-
function.Replace the Yamaha diag-
nostic tool.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.