Yamaha Mt 01 T 2005 Manual

							FUEL INJECTION SYSTEM
7-26
3. Main switch
4. Battery
5. Fuel injection system fuse
8. Main fuse
10.ECU fuse
15.Fuel pump relay
16.Neutral switch
17.Fuel pump
19.Sidestand switch
20.Crankshaft position sensor
21.Throttle position sensor
22.Cylinder-#1 intake air pressure sensor
23.Cylinder-#2 intake air pressure sensor
24.Lean angle cut-off switch
25.Speed sensor
26.Muffler cooling fan temperature sensor
27.Air temperature sensor
28.Engine temperature sensor
29.ECU (electronic control unit)
30.ISC (idle speed control) unit
31.Intake solenoid
32.Spark plug
33.Cylinder-#2 right ignition coil
34.Cylinder-#2 left ignition coil
35.Cylinder-#1 left ignition coil
36.Cylinder-#1 right ignition coil
37.EXUP servo motor
38.Decompression solenoid
39.Injector #1
40.Injector #2
44.Multi-function meter
45.Engine trouble warning light
51.O
2 sensor
70.Auto decompression fuse
73.Engine stop switch
81.Ignition fuse 
						

							FUEL INJECTION SYSTEM
7-27
EAS27350ECU 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 en-
gine 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 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 when 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 appro-
priate substitute characteristic operation, and alerts the rider of the detected malfunction by illuminat-
ing the engine trouble warning light.
After the engine has been stopped, the lowest fault code number appears on the odometer/tripme-
ter/fuel reserve tripmeter LCD. Once a fault code has been displayed, it remains stored in the memory 
of the ECU until it is deleted.
Engine trouble warning light indication and fuel injection system operation
* The warning light flashes when any one of the conditions listed below is present and the start switch 
is pushed:
Checking the engine trouble warning light bulb
The engine trouble warning light comes on for 1.4 seconds after the main switch has been turned to 
“ON” and it comes on while the start switch is being pushed. If the warning light does not come on under 
these conditions, the warning light bulb may be defective.Warning light indica-
tionECU operationFuel injection opera-
tionVehicle operation
Flashing*Warning provided 
when unable to start 
engineOperation stopped Cannot be operated
Fault code No. 63 
detectedOperates Can be operated
Remains on Malfunction detectedOperated with 
substitute 
characteristics in 
accordance with the 
description of the 
malfunctionCan or cannot be 
operated depending on 
the fault code
12: Crankshaft position sensor 41:Lean angle cut-off switch
(open or short-circuit)
19:Blue/yellow ECU lead
(broken or disconnected)50:ECU internal malfunction
(memory check error)
30:Lean angle cut-off switch
(latch up detected) 
						

							FUEL INJECTION SYSTEM
7-28
EAS27380
SELF-DIAGNOSTIC FUNCTION TABLE
If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illumi-
nates 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 to operate or stop operating, depending on the conditions.
Self-Diagnostic Function table
a
b
cc
d
a. Main switch “OFF”
b. Main switch “ON”
c. Engine trouble warning light offd. Engine trouble warning light on for 1.4 
seconds
Fault 
code No.Item SymptomAble / un-
able to startAble / un-
able to 
drive
12Crankshaft position 
sensorNo normal signals are received 
from the crankshaft position 
sensor.Unable Unable
13Cylinder-#1 intake air 
pressure sensor
(open or short circuit)Cylinder-#1 intake air pressure 
sensor: open or short circuit 
detected.Able Able
14Cylinder-#1 intake air 
pressure sensor
(hose line)Cylinder-#1 intake air pressure 
sensor: hose system malfunction 
(clogged or detached hose).Able Able
15Throttle position 
sensor
(open or short circuit)Throttle position sensor: open or 
short circuit detected.Able Able
17EXUP servo motor 
circuit
(open or short circuit)EXUP servo motor circuit: open or 
short circuit detected.Able Able
18EXUP servo motor
(lock)EXUP servo motor is stuck. Able Able
19Blue/yellow ECU lead
(broken or 
disconnected)A break or disconnection of the 
blue/yellow lead of the ECU is 
detected.Unable Unable
22Air temperature 
sensor
(open or short circuit)Air temperature sensor: open or 
short circuit detected.Able Able 
						

							FUEL INJECTION SYSTEM
7-29
24O2 sensorNo normal signal is received from 
the O2 sensor.Able Able
25Cylinder-#2 intake air 
pressure sensor
(open or short circuit)Cylinder-#2 intake air pressure 
sensor: open or short circuit 
detected.Able Able
26Cylinder-#2 intake air 
pressure sensor
(hose system)Cylinder-#2 intake air pressure 
sensor: hose system malfunction 
(clogged or detached hose).Able Able
28Engine temperature 
sensor
(open or short circuit)Engine temperature sensor: open 
or short circuit detected.Able Able
29Decompression 
solenoid (thermistor)
(open or short circuit)Decompression solenoid 
(thermistor): open or short circuit 
detected.Able Able
30Lean angle cut-off 
switch
(latch up detected)The vehicle has overturned. Unable Unable
33Cylinder-#1 left or 
right ignition coil
(faulty ignition)Malfunction detected in the 
primary wire of the cylinder-#1 left 
or right ignition coil.Able
(depending 
on the 
number of 
faulty cylin-
ders)Able
(depending 
on the 
number of 
faulty cylin-
ders)
34Cylinder-#2 left 
ignition coil
(faulty ignition)Malfunction detected in the 
primary wire of the cylinder-#2 left 
ignition coil.Able
(depending 
on the 
number of 
faulty cylin-
ders)Able
(depending 
on the 
number of 
faulty cylin-
ders)
35Cylinder-#1 left or 
right ignition coil
(faulty ignition)Malfunction detected in the 
primary wire of the cylinder-#1 left 
or right ignition coil.Able
(depending 
on the 
number of 
faulty cylin-
ders)Able
(depending 
on the 
number of 
faulty cylin-
ders)
36Cylinder-#2 right 
ignition coil
(faulty ignition)Malfunction detected in the 
primary wire of the cylinder-#2 
right ignition coil.Able
(depending 
on the 
number of 
faulty cylin-
ders)Able
(depending 
on the 
number of 
faulty cylin-
ders)
37ISC valve (stuck fully 
open)Engine speed is high when the 
engine is idling.Able Able
38Decompression 
solenoidDecompression solenoid: open or 
short circuit detected.Able Able
41Lean angle cut-off 
switch
(open or short circuit)Lean angle cut-off switch: open or 
short circuit detected.Unable Unable Fault 
code No.Item SymptomAble / un-
able to startAble / un-
able to 
drive 
						

							FUEL INJECTION SYSTEM
7-30
Communication error with the meter42Speed sensorNo normal signals are received 
from the speed sensor.
Able Able
Neutral switchOpen or short circuit is detected in 
the neutral switch.
43Fuel system voltage
(monitoring voltage)The ECU is unable to monitor the 
battery voltage
(an open or short circuit in the line 
to the ECU).Able Able
44Error in writing the 
amount of CO 
adjustment on 
EEPROMError is detected while reading or 
writing on EEPROM (CO 
adjustment value).Able Able
46Vehicle system power 
supply
(Monitoring voltage)Power supply to the fuel injection 
system is not normal.Able Able
50ECU internal 
malfunction
(memory check error)Faulty ECU memory. (When this 
malfunction is detected in the 
ECU, the fault code number might 
not appear on the meter.)Unable Unable
62Muffler cooling fan 
temperature sensor
(open or short circuit)Muffler cooling fan temperature 
sensor: open or short circuit 
detected.Able Able
63Muffler cooling fan 
temperature sensor 
(ambient temperature 
abnormally high)Engine trouble warning light is 
flashing. (Abnormally high 
temperature is detected by muffler 
cooling fan temperature sensor.)Able Able
Fault 
code No.Item SymptomAble / un-
able to startAble / un-
able to 
drive
Er-1ECU internal 
malfunction
(output signal error)No signals are received from the 
ECU.Unable Unable
Er-2ECU internal 
malfunction
(output signal error)No signals are received from the 
ECU within the specified duration.Unable Unable
Er-3ECU internal 
malfunction
(output signal error)Data from the ECU cannot be 
received correctly.Unable Unable
Er-4ECU internal 
malfunction
(input signal error)Non-registered data has been 
received from the meter.Unable Unable Fault 
code No.Item SymptomAble / un-
able to startAble / un-
able to 
drive 
						

							FUEL INJECTION SYSTEM
7-31
EAS27400TROUBLESHOOTING METHOD
The engine operation is not normal and the 
engine trouble warning light comes on.
1. Check:
Fault code number



 





 
 








 
 



 
 



 



a. Check the fault code number displayed on 
the meter.
b. Identify the faulty system with the fault code. 
Refer to “Self-Diagnostic Function table”.
c. Identify the probable cause of the malfunc-
tion. Refer to “Diagnostic code table”.
        
2. Check and repair the probable cause of mal-
function.
3. Perform ECU reinstatement action.
Refer to “Reinstatement method” of table in 
“TROUBLESHOOTING DETAILS”.4. Turn the main switch to “OFF” and back to 
“ON”, then check that no fault code number is 
displayed.
NOTE:
If fault codes are displayed, repeat steps (1) to 
(4) until no fault code number is displayed.
5. Erase the malfunction history in the diagnos-
tic mode. Refer to “Sensor operation table 
(Diagnostic code No. 62)”.
NOTE:
Turning the main switch to “OFF” 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 following sensors and 
actuators in the Diagnostic mode. Refer to 
“Sensor operation table” and “Actuator oper-
ation table”.
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 inner parts of 
the engine.
EAS27420DIAGNOSTIC MODE
Setting the diagnostic mode
1. Turn the main switch to “OFF” and set the engine stop switch to “”.
2. Disconnect the wire harness coupler from the fuel pump.
3. Press and hold the “RESET” button, turn the main switch to “ON”, and continue to press the button 
for 8 seconds or more.Fault code No. No fault code No.
Check and repair. 
Refer to “TROUBLE-
SHOOTING DE-
TA I L S” on page 7-39.
Monitor the operation 
of the sensors and 
actuators in the 
diagnostic mode. 
Refer to “Sensor 
operation table” and 
“Actuator operation 
table”.Check and repair. 
Refer to “Self-
Diagnostic Function 
table”.
01: Throttle position sensor (throttle angle)
30: Cylinder-#1 left ignition coil
31: Cylinder-#2 left ignition coil
32: Cylinder-#1 right ignition coil
33: Cylinder-#2 right ignition coil
36: Injector #1
37: Injector #2
“RESET”“SELECT” 
						

							FUEL INJECTION SYSTEM
7-32
NOTE:
All displays on the meter disappear except the clock and odometer/trip meter/fuel reserve trip meter 
displays.
“dIAG” appears on the odometer/trip meter/fuel reserve trip meter LCD.
4. Press the “SELECT” button to select the diagnostic mode “dIAG”.
5. After selecting “dIAG”, simultaneously press the “SELECT” and “RESET” buttons for 2 seconds or 
more to activate the diagnostic mode. The diagnostic code number “d01” appears on the clock LCD.
6. Set the engine stop switch to “”.
7. Select the diagnostic code number corresponding to the fault code number by pressing the “SE-
LECT” and “RESET” buttons.
NOTE:
To decrease the selected diagnostic code number, press the “RESET” button. Press the “RESET” 
button for 1 second or longer to automatically decrease the diagnostic code numbers.
To increase the selected diagnostic code number, press the “SELECT” button. Press the “SELECT” 
button for 1 second or longer to automatically increase the diagnostic code numbers.
8. Verify the operation of the sensor or actuator.
Sensor operation
The data representing the operating conditions of the sensor appears on the odometer/trip meter/fu-
el reserve trip meter LCD.
Actuator operation
Set the engine stop switch to “” to operate the actuator.
NOTE:
If the engine stop switch is set to “”, set it to “”, and then set it to “” again.
9. Turn the main switch to “OFF” to cancel the diagnostic mode.
Diagnostic code table
Fault 
code 
No.Symptom Probable cause of malfunctionDiagnostic 
code No.
12No normal signals are 
received from the 
crankshaft position sensor.Open or short circuit in wire harness.
Defective crankshaft position sensor.
Malfunction in pickup rotor.
Malfunction in ECU.
Improperly installed sensor.—
13Cylinder-#1 intake air 
pressure sensor: open or 
short circuit detected.Open or short circuit in wire harness.
Defective cylinder-#1 intake air pressure 
sensor.
Malfunction in ECU.03
“d70     d01”“d01     d70” 
						

							FUEL INJECTION SYSTEM
7-33
14Cylinder-#1 intake air 
pressure sensor: hose 
system malfunction 
(clogged or detached 
hose).Cylinder-#1 intake air pressure sensor hose 
is detached, clogged, kinked, or pinched.
Malfunction in ECU.03
15Throttle position sensor: 
open or short circuit 
detected.Open or short circuit in wire sub lead.
Open or short circuit in wire harness.
Defective throttle position sensor.
Malfunction in ECU.
Improperly installed throttle position sensor.01
17EXUP servo motor circuit: 
open or short circuit 
detected.Open or short circuit in wire harness.
Defective EXUP servo motor 
(potentiometer circuit).53
18 EXUP servo motor is stuck.Open or short circuit in wire harness.
Stuck EXUP servo motor (mechanism).
Stuck EXUP servo motor (motor).53
19A break or disconnection of 
the blue/yellow lead of the 
ECU is detected.Open circuit in wire harness (ECU coupler).
Malfunction in ECU.20
22Air temperature sensor: 
open or short circuit 
detected.Open or short circuit in wire harness.
Defective air temperature sensor.
Malfunction in ECU.
Improperly installed air temperature sensor.05
24No normal signal is 
received from the O
2 
sensor.Open or short circuit in wire harness.
Defective O2 sensor.
Malfunction in ECU.
Improperly installed sensor.—
25Cylinder-#2 intake air 
pressure sensor: open or 
short circuit detected.Open or short circuit in wire harness.
Defective cylinder-#2 intake air pressure 
sensor.
Malfunction in ECU.04
26Cylinder-#2 intake air 
pressure sensor: hose 
system malfunction 
(clogged or detached 
hose).Cylinder-#2 intake air pressure sensor hose 
is detached, clogged, kinked, or pinched.
Malfunction in ECU.04
28Engine temperature 
sensor: open or short 
circuit detected.Open or short circuit in wire sub lead.
Open or short circuit in wire harness.
Defective engine temperature sensor.
Malfunction in ECU.
Improperly installed sensor.11
29Decompression solenoid 
(thermistor): open or short 
circuit detected.Open or short circuit in wire harness.
Defective decompression solenoid 
(thermistor).
Malfunction in ECU.
Improperly installed sensor.55
30The vehicle has 
overturned.Overturned.
Malfunction in ECU.08 Fault 
code 
No.Symptom Probable cause of malfunctionDiagnostic 
code No. 
						

							FUEL INJECTION SYSTEM
7-34
33Malfunction detected in the 
primary wire of the 
cylinder-#1 left or right 
ignition coil.Open or short circuit in wire sub lead.
Open or short circuit in wire harness.
Malfunction in cylinder-#1 left or right 
ignition coil.
Malfunction in ECU.
Malfunction in a component of ignition cut-
off circuit system.30
32
34Malfunction detected in the 
primary wire of the 
cylinder-#2 left ignition coil.Open or short circuit in wire harness.
Malfunction in cylinder-#2 left ignition coil.
Malfunction in ECU.
Malfunction in a component of ignition cut-
off circuit system.31
35Malfunction detected in the 
primary wire of the 
cylinder-#1 left or right 
ignition coil.Open or short circuit in wire sub lead.
Open or short circuit in wire harness.
Malfunction in cylinder-#1 left or right 
ignition coil.
Malfunction in ECU.
Malfunction in a component of ignition cut-
off circuit system.30
32
36Malfunction detected in the 
primary wire of the 
cylinder-#2 right ignition 
coil.Open or short circuit in wire harness.
Malfunction in cylinder-#2 right ignition coil.
Malfunction in ECU.
Malfunction in a component of ignition cut-
off circuit system.33
37Engine speed is high when 
the engine is idling.Open circuit in wire harness.
Malfunction in throttle body.
Malfunction in throttle cables.
ISC valve is stuck fully open due to 
disconnected ISC unit hose or coupler. 
(High engine idle speed is detected with the 
ISC valve stuck fully open even though 
signals for the valve to close are 
continuously being transmitted by the 
ECU.)
Malfunction in ECU.
ECU fuse is blown.54
38Decompression solenoid: 
open or short circuit 
detected.Open or short circuit in wire harness.
Defective decompression solenoid.
Malfunction in ECU.
Improperly installed sensor.55
41Lean angle cut-off switch: 
open or short circuit 
detected.Open or short circuit in wire harness.
Defective lean angle cut-off switch.
Malfunction in ECU.08 Fault 
code 
No.Symptom Probable cause of malfunctionDiagnostic 
code No. 
						

							FUEL INJECTION SYSTEM
7-35
42No normal signals are 
received from the speed 
sensor.
Open circuit is detected in 
the neutral switch.Open circuit in wire harness.
Defective speed sensor.
Malfunction in vehicle speed sensor 
detected.
Defective neutral switch.
Malfunction in the engine side of the neutral 
switch.
Malfunction in ECU.07
21
43The ECU is unable to 
monitor the battery voltage 
(an open or short circuit in 
the line to the ECU).Open or short circuit in wire harness.
Malfunction in ECU.09
44Error is detected while 
reading or writing on 
EEPROM (CO adjustment 
value).Malfunction in ECU. (The CO adjustment 
value is not properly written on or read from 
the internal memory).60
46Power supply to the fuel 
injection system is not 
normal.Malfunction in the charging system. Refer to 
“CHARGING SYSTEM” on page 7-11.—
50Faulty ECU memory. 
(When this malfunction is 
detected in the ECU, the 
fault code number might 
not appear on the meter.)Malfunction in ECU. (The program and data 
are not properly written on or read from the 
internal memory.)—
62Muffler cooling fan 
temperature sensor: open 
or short circuit detected.Open or short circuit in wire harness.
Defective muffler cooling fan temperature 
sensor.
Malfunction in ECU.
Improperly installed sensor.12
63Engine trouble warning 
light is flashing. 
(Abnormally high 
temperature is detected by 
muffler cooling fan 
temperature sensor.)Muffler cover fan fuse or ECU fuse is blown.
Defective muffler cooling fan temperature 
sensor or muffler cooling fan motor relay
Positions of muffler cooling fan temperature 
sensor and its surrounding parts changed 
due to deformed parts near sensor
Muffler cooling fan temperature sensor 
detected a temperature of 120 °C (248 °F) 
or higher.63
Er-1No signals are received 
from the ECU.Open or short circuit in wire harness.
Malfunction in meter.
Malfunction in ECU.
Defective wire connection of the ECU 
coupler.—
Er-2No signals are received 
from the ECU within the 
specified duration.Improper connection in wire harness.
Malfunction in meter.
Malfunction in ECU.—
Er-3Data from the ECU cannot 
be received correctly.Improper connection in wire harness.
Malfunction in meter.
Malfunction in ECU.— Fault 
code 
No.Symptom Probable cause of malfunctionDiagnostic 
code No.