Yamaha XV19SW(C), XV19W(C), XV19MW(C), XV19CTSW(C), XV19CTW(C), XV19CTMW(C). Service Manual - part 24

FUEL INJECTION SYSTEM

7-28

3. Main switch
4. Main fuse
6. Battery
7. Fuel injection system fuse
11.Relay unit
12.Starting circuit cut-off relay
13.Fuel pump relay
14.Neutral switch
15.Diode 2
16.Sidestand switch
17.Fuel pump
19.Crankshaft position sensor
20.Throttle position sensor
21.Cylinder-#1 intake air pressure sensor
22.Cylinder-#2 intake air pressure sensor
23.Lean angle sensor
24.Speed sensor
25.Air temperature sensor
26.Engine temperature sensor
27.ECU (electronic control unit)
28.Cylinder-#1 left ignition coil
29.Cylinder-#1 right ignition coil
30.Cylinder-#2 left ignition coil
31.Cylinder-#2 right ignition coil
32.Spark plug
33.ISC (idle speed control) unit
34.EXUP servo motor
35.Injector #1
36.Injector #2
37.O

2

 sensor

40.Multi-function meter
41.Reset switch
42.Engine trouble warning light
52.Headlight relay
55.Dimmer switch
58.Select switch
64.Headlight (high beam)
65.Headlight (low beam)
68.Engine stop switch
77.Ignition fuse
78.Headlight fuse
79.Signaling system fuse
81.ECU fuse

FUEL INJECTION SYSTEM

7-29

EAS27350

ECU 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/clock 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

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 (LED) may be defective.

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-
function

Can or cannot be oper-
ated depending on the 
fault code

12:

Crankshaft position sensor

41:

Lean angle sensor
(open or short-circuit)

19:

Blue/black ECU lead
(broken or disconnected)

50:

ECU internal malfunction
(memory check error)

30:

Lean angle sensor
(latch up detected)

a

b

c

c

d

a. Main switch “OFF”
b. Main switch “ON”
c. Engine trouble warning light off
d. Engine trouble warning light on for 1.4 

seconds

FUEL INJECTION SYSTEM

7-30

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

Fault 

code No.

Item

Symptom

Able / un-

able to start

Able / un-

able to 

drive

12

Crankshaft position 
sensor

No normal signals are received 
from the crankshaft position sen-
sor.

Unable

Unable

13

Cylinder-#1 intake air 
pressure sensor
(open or short circuit)

Cylinder-#1 intake air pressure 
sensor: open or short circuit de-
tected.

Able

Able

14

Cylinder-#1 intake air 
pressure sensor
(hose system)

Cylinder-#1 intake air pressure 
sensor: hose system malfunction 
(clogged or detached hose).

Able

Able

15

Throttle position sen-
sor
(open or short circuit)

Throttle position sensor: open or 
short circuit detected.

Able

Able

17

EXUP servo motor 
circuit
(open or short circuit)

EXUP servo motor circuit: open or 
short circuit detected.

Able

Able

18

EXUP servo motor
(lock)

EXUP servo motor is stuck.

Able

Able

19

Blue/black ECU lead
(broken or discon-
nected)

A break or disconnection of the 
blue/black lead of the ECU is de-
tected.

Unable

Unable

22

Air temperature sen-
sor
(open or short circuit)

Air temperature sensor: open or 
short circuit detected.

Able

Able

24

O

2

 sensor

No normal signal is received from 
the O

2

 sensor.

Able

Able

25

Cylinder-#2 intake air 
pressure sensor
(open or short circuit)

Cylinder-#2 intake air pressure 
sensor: open or short circuit de-
tected.

Able

Able

26

Cylinder-#2 intake air 
pressure sensor
(hose system)

Cylinder-#2 intake air pressure 
sensor: hose system malfunction 
(clogged or detached hose).

Able

Able

28

Engine temperature 
sensor
(open or short circuit)

Engine temperature sensor: open 
or short circuit detected.

Able

Able

30

Lean angle sensor
(latch up detected)

The vehicle has overturned.

Unable

Unable

FUEL INJECTION SYSTEM

7-31

33

Cylinder-#1 left or 
right ignition coil
(faulty ignition)

Malfunction detected in the prima-
ry 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)

34

Cylinder-#2 left or 
right ignition coil
(faulty ignition)

Malfunction detected in the prima-
ry wire of the cylinder-#2 left or 
right ignition coil.

Able
(depending 
on the 
number of 
faulty cylin-
ders)

Able
(depending 
on the 
number of 
faulty cylin-
ders)

35

Cylinder-#1 left or 
right ignition coil
(faulty ignition)

Malfunction detected in the prima-
ry 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)

36

Cylinder-#2 left or 
right ignition coil
(faulty ignition)

Malfunction detected in the prima-
ry wire of the cylinder-#2 left or 
right ignition coil.

Able
(depending 
on the 
number of 
faulty cylin-
ders)

Able
(depending 
on the 
number of 
faulty cylin-
ders)

37

ISC valve (stuck fully 
open)

Engine speed is high when the en-
gine is idling.

Able

Able

41

Lean angle sensor
(open or short circuit)

Lean angle sensor: open or short 
circuit detected.

Unable

Unable

42

Speed sensor

No normal signals are received 
from the speed sensor.

Able

Able

Neutral switch

Open or short circuit is detected in 
the neutral switch.

43

Fuel 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

44

Error in writing the 
amount of CO adjust-
ment on EEPROM

Error is detected while reading or 
writing on EEPROM (CO adjust-
ment value).

Able

Able

46

Vehicle system power 
supply
(Monitoring voltage)

Power supply to the fuel injection 
system is not normal.

Able

Able

50

ECU internal malfunc-
tion
(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

Fault 

code No.

Item

Symptom

Able / un-

able to start

Able / un-

able to 

drive

FUEL INJECTION SYSTEM

7-32

Communication error with the meter

EAS27400

TROUBLESHOOTING 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.

70

Engine idling stop

Engine has been left idling. (The 
ECU automatically stops the en-
gine after 20 minutes if it is left 
idling.)

Able

Able

Fault 

code No.

Item

Symptom

Able / un-

able to start

Able / un-

able to 

drive

Er-1

ECU internal malfunc-
tion
(output signal error)

No signals are received from the 
ECU.

Unable

Unable

Er-2

ECU internal malfunc-
tion
(output signal error)

No signals are received from the 
ECU within the specified duration.

Unable

Unable

Er-3

ECU internal malfunc-
tion
(output signal error)

Data from the ECU cannot be re-
ceived correctly.

Unable

Unable

Er-4

ECU internal malfunc-
tion
(input signal error)

Non-registered data has been re-
ceived from the meter.

Unable

Unable

Fault 

code No.

Item

Symptom

Able / un-

able to start

Able / un-

able to 

drive

Fault code No.

No fault code No.

Check and repair. 
Refer to “TROUBLE-
SHOOTING DE-
TAILS” on page 7-40.
Monitor the opera-
tion of the sensors 
and actuators in the 
diagnostic mode. Re-
fer to “Sensor opera-
tion table” and 
“Actuator operation 
table”.

Check and repair. 
Refer to “Self-Diag-
nostic Function ta-
ble”.

FUEL INJECTION SYSTEM

7-33

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.

EAS27420

DIAGNOSTIC 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” switch, turn the main switch to “ON”, and continue to press the switch 

for 8 seconds or more.

NOTE:

• All displays on the meter disappear except the clock and odometer/trip meter/fuel reserve trip 

meter/clock displays.

• “dIAG” appears on the odometer/trip meter/fuel reserve trip meter/clock LCD.

4. Simultaneously press the “SELECT” and “RESET” switches for 2 seconds or more to activate the 

diagnostic mode. The diagnostic code number “d01” appears on the clock LCD.

5. Set the engine stop switch to “

”.

6. Select the diagnostic code number corresponding to the fault code number by pressing the “SE-

LECT” and “RESET” switches.

NOTE:

• To decrease the selected diagnostic code number, press the “RESET” switch. Press the “RESET” 

switch for 1 second or longer to automatically decrease the diagnostic code numbers.

• To increase the selected diagnostic code number, press the “SELECT” switch. Press the “SELECT” 

switch for 1 second or longer to automatically increase the diagnostic code numbers.

01: Throttle position sensor (throttle angle)
30: Cylinder-#1 ignition coil
31: Cylinder-#2 ignition coil
32: Cylinder-#1 ignition coil
33: Cylinder-#2 ignition coil
36: Injector #1
37: Injector #2

“SELECT”

“RESET”

FUEL INJECTION SYSTEM

7-34

7. 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/clock 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.

8. Turn the main switch to “OFF” to cancel the diagnostic mode.

Diagnostic code table

Fault 
code 

No.

Symptom

Probable cause of malfunction

Diagnostic 

code No.

12

No normal signals are re-
ceived from the crankshaft 
position sensor.

• Open or short circuit in wire harness.
• Defective crankshaft position sensor.
• Malfunction in crankshaft position sensor 

rotor.

• Malfunction in ECU.
• Improperly installed sensor.

—

13

Cylinder-#1 intake air pres-
sure sensor: open or short 
circuit detected.

• Open or short circuit in wire harness.
• Defective cylinder-#1 intake air pressure 

sensor.

• Malfunction in ECU.

03

14

Cylinder-#1 intake air pres-
sure sensor: hose system 
malfunction (clogged or de-
tached hose).

• Cylinder-#1 intake air pressure sensor hose 

is detached, clogged, kinked, or pinched.

• Malfunction in ECU.

03

15

Throttle position sensor: 
open or short circuit detect-
ed.

• 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

17

EXUP servo motor circuit: 
open or short circuit detect-
ed.

• Open or short circuit in wire harness.
• Defective EXUP servo motor (potentiome-

ter 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

d01”

“d01 d70”

“d70

FUEL INJECTION SYSTEM

7-35

19

A break or disconnection of 
the blue/black lead of the 
ECU is detected.

• Open circuit in wire harness (ECU coupler).
• Malfunction in ECU.

20

22

Air temperature sensor: 
open or short circuit detect-
ed.

• Open or short circuit in wire harness.
• Defective air temperature sensor.
• Malfunction in ECU.
• Improperly installed air temperature sensor.

05

24

No normal signal is re-
ceived from the O

2

 sensor.

• Open or short circuit in wire harness.
• Defective O

2

 sensor.

• Malfunction in ECU.
• Improperly installed sensor.

—

25

Cylinder-#2 intake air pres-
sure sensor: open or short 
circuit detected.

• Open or short circuit in wire sub lead.
• Open or short circuit in wire harness.
• Defective cylinder-#2 intake air pressure 

sensor.

• Malfunction in ECU.

04

26

Cylinder-#2 intake air pres-
sure sensor: hose system 
malfunction (clogged or de-
tached hose).

• Cylinder-#2 intake air pressure sensor hose 

is detached, clogged, kinked, or pinched.

• Malfunction in ECU.

04

28

Engine temperature sen-
sor: 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

30

The vehicle has over-
turned.

• Overturned.
• Malfunction in ECU.

08

33

Malfunction detected in the 
primary wire of the cylin-
der-#1 left or right ignition 
coil.

• Open or short circuit in wire harness.
• Malfunction in cylinder-#1 left or right igni-

tion coil.

• Malfunction in ECU.
• Malfunction in a component of ignition cut-

off circuit system.

30
32

34

Malfunction detected in the 
primary wire of the cylin-
der-#2 left or right ignition 
coil.

• Open or short circuit in wire sub lead.
• Open or short circuit in wire harness.
• Malfunction in cylinder-#2 left or right igni-

tion coil.

• Malfunction in ECU.
• Malfunction in a component of ignition cut-

off circuit system.

31
33

35

Malfunction detected in the 
primary wire of the cylin-
der-#1 left or right ignition 
coil.

• Open or short circuit in wire harness.
• Malfunction in cylinder-#1 left or right igni-

tion coil.

• Malfunction in ECU.
• Malfunction in a component of ignition cut-

off circuit system.

30
32

Fault 
code 

No.

Symptom

Probable cause of malfunction

Diagnostic 

code No.

FUEL INJECTION SYSTEM

7-36

36

Malfunction detected in the 
primary wire of the cylin-
der-#2 left or right ignition 
coil.

• Open or short circuit in wire sub lead.
• Open or short circuit in wire harness.
• Malfunction in cylinder-#2 left or right igni-

tion coil.

• Malfunction in ECU.
• Malfunction in a component of ignition cut-

off circuit system.

31
33

37

Engine 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 discon-

nected ISC unit hose or coupler. (High en-
gine 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

41

Lean angle sensor: open or 
short circuit detected.

• Open or short circuit in wire harness.
• Defective lean angle sensor.
• Malfunction in ECU.

08

42

No normal signals are re-
ceived from the speed sen-
sor.
Open circuit is detected in 
the neutral switch.

• Open circuit in wire harness.
• Defective speed sensor.
• Malfunction in vehicle speed sensor detect-

ed.

• Defective neutral switch.
• Malfunction in the engine side of the neutral 

switch.

• Malfunction in ECU.

07
21

43

The ECU is unable to moni-
tor 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

44

Error is detected while 
reading or writing on EE-
PROM (CO adjustment val-
ue).

• Malfunction in ECU. (The CO adjustment 

value is not properly written on or read from 
the internal memory).

60

46

Power supply to the fuel in-
jection system is not nor-
mal.

Malfunction in the charging system. Refer to 
“CHARGING SYSTEM” on page 7-13.

—

50

Faulty 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.)

—

Er-1

No 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 cou-

pler.

—

Fault 
code 

No.

Symptom

Probable cause of malfunction

Diagnostic 

code No.

FUEL INJECTION SYSTEM

7-37

Sensor operation table

Er-2

No signals are received 
from the ECU within the 
specified duration.

• Improper connection in wire harness.
• Malfunction in meter.
• Malfunction in ECU.

—

Er-3

Data from the ECU cannot 
be received correctly.

• Improper connection in wire harness.
• Malfunction in meter.
• Malfunction in ECU.

—

Er-4

Non-registered data has 
been received from the 
meter.

• Improper connection in wire harness.
• Malfunction in meter.
• Malfunction in ECU.

—

Diag-

nostic 

code 

No.

Item

Meter display

Checking method

01

Throttle angle

• Fully closed position

12–22

Check with throttle fully 
closed.

• Fully opened position

87–107

Check with throttle fully 
open.

03

Pressure difference
(atmospheric pressure and 
cylinder-#1 intake air pres-
sure)

Displays the cylinder-#1 in-
take air pressure.

Set the engine stop switch 
to “

”, and then push the 

start switch “

”. (If the dis-

play value changes, the 
performance is OK.)

04

Pressure difference
(atmospheric pressure and 
cylinder-#2 intake air pres-
sure)

Displays the cylinder-#2 in-
take air pressure.

Set the engine stop switch 
to “

”, and then push the 

start switch “

”. (If the dis-

play value changes, the 
performance is OK.)

05

Air temperature

Displays the air temperature.

Compare the actually mea-
sured air temperature with 
the meter display value.

07

Vehicle speed pulse

0–999

Check that the number in-
creases when the rear 
wheel is rotated. The num-
ber is cumulative and does 
not reset each time the 
wheel is stopped.

08

Lean angle sensor

Remove the lean angle 
sensor and incline it more 
than 65 degrees.

• Upright

0.4–1.4

• Overturned

3.7–4.4

Fault 
code 

No.

Symptom

Probable cause of malfunction

Diagnostic 

code No.

FUEL INJECTION SYSTEM

7-38

09

Fuel system voltage
(battery voltage)

Approximately 12.0

Set the engine stop switch 
to “

”, and then compare 

with the actually measured 
battery voltage. (If the bat-
tery voltage is lower, per-
form recharging.)

11

Engine temperature

Displays the engine tempera-
ture.

Compare the actually mea-
sured engine temperature 
with the meter display val-
ue.

20

Sidestand switch

Set on/off the sidestand 
switch (with the transmis-
sion in gear).

• Stand retracted

ON

• Stand extended

OFF

21

Neutral switch

Shift the transmission.

• Neutral

ON

• In gear

OFF

53

EXUP servo motor

Displays the operating angle.
Engine trouble warning light 
comes on twice: once when 
the EXUP valve is closing 
and once when it is opening.

—

60

EEPROM fault code dis-
play

—

• No history

00

• History exists

01 or 02 (Cylinder fault code)
• (If both cylinders are defec-

tive, the display alternates 
every two seconds.)

61

Malfunction history code 
display

—

• No history

00

• History exists

Fault codes 12-70
• (If more than one code 

number is detected, the dis-
play alternates every two 
seconds to show all the de-
tected code numbers. 
When all code numbers are 
shown, the display repeats 
the same process.)

62

Malfunction history code 
erasure

• No history

0

—

• History exists

Up to 25 fault codes

To erase the history, set the 
engine stop switch to “

”.

Diag-

nostic 

code 

No.

Item

Meter display

Checking method

FUEL INJECTION SYSTEM

7-39

Actuator operation table

70

Control number

0–255

—

Diag-

nostic 

code 

No.

Item

Actuation

Checking method

30

Cylinder-#1 left or right ig-
nition coil

Actuates the cylinder-#1 left 
or right ignition coil five times 
at one-second intervals.
Illuminates the engine trou-
ble warning light.

Check the spark five times.
• Connect an ignition 

checker.

31

Cylinder-#2 left or right ig-
nition coil

Actuates the cylinder-#2 left 
or right ignition coil five times 
at one-second intervals.
Illuminates the engine trou-
ble warning light.

Check the spark five times.
• Connect an ignition 

checker.

32

Cylinder-#1 left or right ig-
nition coil

Actuates the cylinder-#1 left 
or right ignition coil five times 
at one-second intervals.
Illuminates the engine trou-
ble warning light.

Check the spark five times.
• Connect an ignition 

checker.

33

Cylinder-#2 left or right ig-
nition coil

Actuates the cylinder-#2 left 
or right ignition coil five times 
at one-second intervals.
Illuminates the engine trou-
ble warning light.

Check the spark five times.
• Connect an ignition 

checker.

36

Injector #1

Actuates the injector #1 five 
times at one-second inter-
vals.
Illuminates the engine trou-
ble warning light.

Check the operating sound 
of the injector #1 five times.

37

Injector #2

Actuates the injector #2 five 
times at one-second inter-
vals.
Illuminates the engine trou-
ble warning light.

Check the operating sound 
of the injector #2 five times.

50

Fuel pump relay

Actuates the fuel pump relay 
five times at one-second in-
tervals.
Illuminates the engine trou-
ble warning light.
(The engine trouble warning 
light is OFF when the relay is 
ON, and the engine trouble 
warning light is ON when the 
relay is OFF).

Check the operating sound 
of the fuel pump relay five 
times.

Diag-

nostic 

code 

No.

Item

Meter display

Checking method

FUEL INJECTION SYSTEM

7-40

EAS27460

TROUBLESHOOTING DETAILS

This section describes the measures per fault code number displayed on the meter. Check and service 
the items or components that are the probable cause of the malfunction following the order given.
After the check and service of the malfunctioning part has been completed, reset the meter display ac-
cording to the reinstatement method.
Fault code No.:
Code number displayed on the meter when the engine failed to work normally. Refer to “Self-Diagnostic 
Function table”.
Diagnostic code No.:
Diagnostic code number to be used when the diagnostic mode is operated. Refer to “DIAGNOSTIC 
MODE” on page 7-33.

52

Headlight relay

Actuates the headlight relay 
for five cycles of five sec-
onds. (ON 2 seconds, OFF 3 
seconds)
Illuminates the engine trou-
ble warning light and head-
light.

Check the operating sound 
of the headlight relay five 
times.

54

ISC valve

Actuates and fully closes the 
ISC valve, then opens it to 
the standby opening position 
when the engine is started. 
This operation takes approxi-
mately 12 seconds until it is 
completed.
Illuminates the engine trou-
ble warning light.

The ISC unit vibrates when 
the ISC valve operates.

Diag-

nostic 

code 

No.

Item

Actuation

Checking method

FUEL INJECTION SYSTEM

7-41

Fault code No.

12

Symptom No normal signals are received from the crankshaft posi-

tion sensor.

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Installed condition of crankshaft posi-
tion sensor.

Check for looseness or pinching.

Cranking the 
engine.

2

Connections
• Crankshaft position sensor coupler
• Main wire harness ECU coupler

• Check the coupler for any pins 

that may be pulled out.

• Check the locking condition of 

the coupler.

• If there is a malfunction, repair it 

and connect the coupler se-
curely.

3

Open or short circuit in wire harness.

• Repair or replace if there is an 

open or short circuit.

• Between the crankshaft position 

sensor coupler and ECU cou-
pler.
(gray–gray)
(black/blue–black/blue)

4

Defective crankshaft position sensor.

• Replace if defective.

Refer to “CHECKING THE 
CRANKSHAFT POSITION 
SENSOR” on page 7-84.

FUEL INJECTION SYSTEM

7-42

Fault code No.

13

Symptom Cylinder-#1 intake air pressure sensor: open or short cir-

cuit detected.

Diagnostic code No.

03

Cylinder-#1 intake air pressure sensor

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Connections
• Cylinder-#1 intake air pressure sen-

sor coupler

• Main wire harness ECU coupler

• Check the coupler for any pins 

that may be pulled out.

• Check the locking condition of 

the coupler.

• If there is a malfunction, repair it 

and connect the coupler se-
curely.

Turning the 
main switch to 
“ON”.

2

Open or short circuit in wire harness.

• Repair or replace if there is an 

open or short circuit.

• Between cylinder-#1 intake air 

pressure sensor coupler and 
ECU coupler
(black/blue–black/blue)
(pink/white–pink/white)
(blue–blue)

3

Defective cylinder-#1 intake air pres-
sure sensor.

• Execute the diagnostic mode. 

(Code No.03)

• Replace if defective.

Refer to “CHECKING THE IN-
TAKE AIR PRESSURE SEN-
SOR” on page 7-90.

FUEL INJECTION SYSTEM

7-43

Fault code No.

14

Symptom Cylinder-#1 intake air pressure sensor: hose system mal-

function (clogged or detached hose).

Diagnostic code No.

03

Cylinder-#1 intake air pressure sensor

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Cylinder-#1 intake air pressure sensor 
hose

• Check the cylinder-#1 intake air 

pressure sensor hose condition.

• Repair or replace the sensor 

hose.

Starting the en-
gine and oper-
ating it at idle.

2

Cylinder-#1 intake air pressure sensor 
malfunction at intermediate electrical 
potential.

• Check and repair the connec-

tion.

• Replace it if there is a malfunc-

tion.

3

Connections
• Cylinder-#1 intake air pressure sen-

sor coupler

• Main wire harness ECU coupler

• Check the coupler for any pins 

that may be pulled out.

• Check the locking condition of 

the coupler.

• If there is a malfunction, repair it 

and connect the coupler se-
curely.

4

Defective cylinder-#1 intake air pres-
sure sensor.

• Execute the diagnostic mode. 

(Code No.03)

• Replace if defective.

Refer to “CHECKING THE IN-
TAKE AIR PRESSURE SEN-
SOR” on page 7-90.