2016 YAMAHA WR 450F check engine

THROTTLE BODY
8-10
EAS2GC1352CHECKING THE INJECTOR
1. Check:• InjectorsObstruction  Replace, and check the fuel
pump and the fuel injection system.
Refer to “FUEL INJECTION SYSTEM” on
page 9-28.
Deposits  Replace.
Damage  Replace.
2. Check:
• Injector resistanceRefer to “CHECKING THE FUEL INJEC-
TOR” on page 9-81.
EAS2GC1353CHECKING THE THROTTLE BODY
1. Check:• Throttle bodyCracks/damage  Replace.
2. Check:
• Fuel passagesObstructions  Clean.
ECA
NOTICE
• Before removing the throttle body, clean
the area around the throttle body to pre-
vent dirt and other foreign material from
falling into the engine.
• If the throttle body is subject to strong shocks or dropped during cleaning, re-
place it.
• Do not use any caustic carburetor clean- ing solution.
• Do not directly push the throttle valves to open them.
• Do not loosen the throttle valve stopper screw “1”, throttle valve pulley nut “2”, or
throttle valve screw “3”. A loss of perfor-
mance may occur.
• Do not use compressed air to clean the throttle body. Foreign materials may ad-
here to the intake air pressure sensor pas-
sage “a” and fuel injector “b” in the
throttle body. 3. Check:
• Starter knob/idle screw passage “c”Obstruction  Blow out with compressed
air.
EAS2GC1354CHECKING THE THROTTLE BODY JOINT
1. Check: • Throttle body joint “1”Crack/damage  Replace.
1
2
3
ba
c
1

IGNITION SYSTEM
9-4
EAS2GC1360TROUBLESHOOTING
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. Air filter case cover1. 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 SPARK
PLUG” on page 3-40. 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 

ELECTRIC STARTING SYSTEM
9-11
8. Check the main relay.Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the main relay.
OK 
9. Check the neutral switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the neutral switch.
OK 
10.Check the clutch switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the clutch switch.
OK 
11.Check the engine stop switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the engine stop switch.
OK 
12.Check the start switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the start switch.
OK 
13.Check the entire starting system’s wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-6. NG

Properly connect or repair the starting sys-
tem’s wiring.
OK 
Replace the ECU.

FUEL INJECTION SYSTEM
9-30
EAS2GC1375ECU 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 illuminat es the engine trouble warning light to alert the
rider that a malfunction has occurred in the syst em. 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 th e self-diagnostic function, the ECU provides an ap-
propriate substitute characteristic operation, and al erts 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 foll owing 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-
tion ECU operation Fuel injection opera-
tion Vehicle operation
Flashing* Warning provided when unable to start
engine Operation 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
cd c

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.
EAS2GC1376TROUBLESHOOTING 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 disp layed 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 an d actuators in the diagnostic mode. Refer to
“TROUBLESHOOTING DETAILS” on page 9-35.
If a malfunction is detected in the sensors or ac tuators, repair or replace all faulty parts.
If no malfunction is detected in the sensors and ac tuators, 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. ConditionThe 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 start 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 th e malfunction detection and code reading is
displayed.
EAS2GC1378TROUBLESHOOTING DETAILS
This section describes the measures per fault c ode 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
Item Crankshaft position sensor: no normal signals are received
from the crankshaft position sensor.
Fail-safe system Unable to start engine
Unable to drive vehicle
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance 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
9-36
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. Crank the engine.
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 the crankshaft posi-
tion sensor coupler and ECU
coupler.
black/blue–black/blue
gray–gray Crank the engine.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Installed condition of crank- shaft position sensor.
Check for looseness or
pinching.
Check the gap between the
crankshaft position sensor
and the pickup rotor. Improperly installed sensor

Reinstall or replace the
sensor.
Refer to “GENERATOR AND
STARTER CLUTCH” on
page 6-63. Crank the engine.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Defective crankshaft position sensor. Check the crankshaft position
sensor.
Refer to “CHECKING THE
CRANKSHAFT POSITION
SENSOR” on page 9-74. Crank the engine.
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. 12
Item Crankshaft position sensor: no normal signals are received
from the crankshaft position sensor.

FUEL INJECTION SYSTEM
9-37
TIP
• If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault
code No. 13 first.
• Before troubleshooting, disconnect the star ter motor lead from the starter relay.
Fault code No. 13
Item Intake air pressure sensor: open or short circuit detected.
Fail-safe system Able to start engine
Able to drive vehicle
Diagnostic code No. 03
Diagnostic tool display Displays the intake air pressure.
Procedure Operate the throttle while pushing the start switch.(If the display
value changes, the performance is OK.)
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Connection of intake air pres- sure 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 intake air pressure
sensor coupler and ECU cou-
pler.
black/blue–black/blue
pink–pink
blue–blue 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 Installed condition of intake air pressure 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.