Yamaha XV19SW(C), XV19W(C), XV19MW(C), XV19CTSW(C), XV19CTW(C), XV19CTMW(C). Service Manual - part 26

FUEL INJECTION SYSTEM

7-60

Fault code No.

46

Symptom Power supply to the fuel injection system is not normal.

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Connections
• 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.

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

2

Faulty battery.

• Replace or charge the battery

Refer to “CHECKING AND 
CHARGING THE BATTERY” on 
page 7-76.

3

Malfunction in rectifier/regulator

• Replace if defective.

Refer to “CHARGING SYS-
TEM” on page 7-13.

4

Open or short circuit in wire harness.

• Repair or replace if there is an 

open or short circuit.

• Between battery and main fuse

(red–red)

• Between main fuse and main 

switch
(red–red)

• Between main switch and igni-

tion fuse
(brown/blue–brown/blue)

• Between ignition fuse and ECU

(red/white–red/white)

Fault code No.

50

Symptom Faulty ECU memory. (When this malfunction is detected in 

the ECU, the fault code number might not appear on the 
meter.)

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Malfunction in ECU.

Replace the ECU.

NOTE:

Do not perform this procedure 
with the main switch turned to 
“ON”.

Turning the 
main switch to 
“ON”.

FUEL INJECTION SYSTEM

7-61

Fault code No.

Er-1 Symptom No signals are received from the ECU.

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Connections
• Main wire harness ECU coupler
• Main wire harness meter assembly 

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 meter assembly cou-

pler and ECU coupler
(yellow/blue–yellow/blue)

3

Malfunction in meter assembly.

Replace the meter assembly.

4

Malfunction in ECU.

Replace the ECU.

Fault code No.

Er-2 Symptom No signals are received from the ECU within the specified 

duration.

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Connections
• Main wire harness ECU coupler
• Main wire harness meter assembly 

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 meter assembly cou-

pler and ECU coupler
(yellow/blue–yellow/blue)

3

Malfunction in meter assembly.

Replace the meter assembly.

4

Malfunction in ECU.

Replace the ECU.

FUEL INJECTION SYSTEM

7-62

Fault code No.

Er-3 Symptom Data from the ECU cannot be received correctly.

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Connections
• Main wire harness ECU coupler
• Main wire harness meter assembly 

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 meter assembly cou-

pler and ECU coupler
(yellow/blue–yellow/blue)

3

Malfunction in meter assembly.

Replace the meter assembly.

4

Malfunction in ECU.

Replace the ECU.

Fault code No.

Er-4 Symptom Non-registered data has been received from the meter.

Diagnostic code No.

—

—

Order Item/components and probable 

cause

Check or maintenance job

Reinstatement 
method

1

Connections
• Main wire harness ECU coupler
• Main wire harness meter assembly 

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 meter assembly cou-

pler and ECU coupler
(yellow/blue–yellow/blue)

3

Malfunction in meter assembly.

Replace the meter assembly.

4

Malfunction in ECU.

Replace the ECU.

FUEL PUMP SYSTEM

7-63

EAS27550

FUEL PUMP SYSTEM

EAS27560

CIRCUIT DIAGRAM

W

W

W

R

R

/

G

B

(GRA

Y)

ON

OFF

R

Br

R

Br

L

R

L

/

Y

Br

L

L

/

B

R

R

R

R

R

B

B

B

R

R

R

B

R

/

Y

L

B

R

/

WR

/

W

R

/

Y

R

Y

R

/

W

R

/

W

R

/

L

R

L

/

Y

L

R

R

Y

L

/

W

Sb

W

Sb

L

L

B

Y

R

R

/

L

L

GS

b

W

L

L

W

R

/

W

L

R

/

Y

L

/

RB

/

Y

L

/

YS

b

L

G

B

(BLUE)

L

/

G

B

(BLUE)

B

B

L

G

R

/

W

Sb

B

Sb

B

B

B

Y

L

Y

Y

B

B

L

L

Y

(BLA

CK)

L

B

B

/

L

Gy

Gy

B

Gy

B

/

L

B

/

L

L

P

/

Y

B

/

L

L

P

W

P

W

(BLA

CK)

B

/

L

L

P

/

Y

(BLA

CK)

B

/

L

L

W

L

B

L

W

/

Y

B

/

L

L

B

/

L

W

/

Y

G

W

B

/

L

B

/

W

(BLA

CK)

(BLA

CK)

Br

B

Br

Br

Br

B

B

B

B

Br

W

B

/

L

B

G

/

W

R

L

B

R

/

L

G

W

B

B

B

/

L

L

Y

/

G

B

L

Y

/

G

L

Br

Br

/

L

Br

/

L

R

Br

L

R

/

B

Br

/

L

R

/

W

R

Y

B

Br

Br

B

R

/

B

Br

L

R

Y

Br

BB

Br
Y

Y

/

B

R

/

Y

G

L

Br

Y

/

B

G

/

L

R

/

Y

Br

(GRAY)

(GRAY)

(GRAY)

(GRAY)

(GRAY)

B

B

G

Y

/

B

(BLUE)

(BLUE)

YG

/

L

(GRAY)

(BLACK)

BB

R

/

W

B

R

G

/

L

/

B

(BLACK)

B

L

B

B

L

B

L

Y

B

B

/

R

Y

B

G

y

R

y

R

O

O

Gy

W

B

/

G

B

B

Gy

Y

G

Br

/

L

B

/

Y

Y

L

Gy

L

R

L

/

B

R

L

R

W

Y

W

/

Y

W

/

R

W

/

G

R

/

B

R

/

B

R

G

Br

Gy

G

P

/

W

P

L

P

Y

Br

W

B

Br

B

Br

B

/

L

L

W

L

(BLA

CK)

B

B

(L)

N

(R)

(BLACK)

(BLACK)

B

B

Dg

L

Dg
L

B

L

Dg

PUSH

B

Y

B

Y

(BLA

CK)

(BLA

CK)

G
B

B

B

A

Y

Y

A

Ch

Ch

Dg

Dg

B

B

/

W

P

Br

BG

R

B

R

B

G

P

L

W

/

G

/

L

P

L

W

/

G

Br

/

L

R

G

P

/

L

W

G

Br

/

L

Gy

/

R

Gy

/

R

Gy

/

R

Gy

R

R

/

G

P

/

L

W

/

G

B

/

L

R

/

G

P

/

L

W

G

Br

L

R

/

G

R

/

B

R

/

B

R

/

B

R

/

B

R

/

B

R

/

B

D

D

C

C

D

D

Y

B

Gy

/

W

W

R

B

/

G

B

R

W

R

(BLA

CK)

L

W

/

R

B

GB

R

B

L

L

B

/

G

B

/

R

B

/

L

W

G

(GRA

Y)

W

G

(D

ARK GRA

Y)

Gy

G

G

Gy

G

B

Gy

Gy

B

W

(BLACK)

R

/

L

B

L

Gy

/

G

Gy

/

W

BB

WL

R

L

Gy

/

W

Gy

/

G

B

L

Sb

/

W

Dg

Ch

Y

G

/

B

G

G

/

Y

Y

/

L

R

/

G

G

/

W

R

/

W

L

L

Ch

Sb

W

Y

R

/

W

Dg

L

Sb

Y

Ch

R

W

Dg

(BLACK)

G

W

B

Y

/

L

G

R

G

(BLACK)

(BLACK)

(BLACK)

G

W

B

Y

/

L

G

R

/

G

G

Y

G

Y

G

/

B

G

B

B

(GRAY)

(GRAY)

B

B

Ch

L

Ch
L

B

L

Ch

Gy

/

R

Gy

R

Gy

R

Gy

R

C

O

O

B

/

R

B

/

R

B

/

R

B

/

R

B

/

R

B

/

R

O

O

Y

L

Gy

/

G

R

/

W

L

Y

Gy

P

Y

B

Y

Y

/

G

L

/

R

R

L

R

B

R

B

P

/

W

Br

Br

W

L

/

W

W

/

Y

B

L

L

/

B

B

B

B

/

Br

B

/

Br

R

/

W

B

/

R

R

W

B

/

R

Br

B

/

W

B

Y

/

R

W

/

Y

Br

/

W

Y

R

P

G

Y

G

L

B

Y

L

/

Y

Y

Dg

G

/

B

B

Ch

G

Y

G

B

B

Ch

Dg

B

B

B

L

G

/

L

L

/

W

B

/

R

R

/

W

Y

Br

W

B

B

L

/

B

L

/

B

P

Br

(BLA

CK)

(BLA

CK)

B

R

W

W

B

W

W

B

G

B

G

B

L

L

A

(BLACK)

(BLACK)

R

/

Y

R

L

(GRAY)

L

BL

Y

(GRAY)

L

B

/

Y

W

W
W

Y

R

Br

W

B

W

Y

Br

Y

G

G

L

R

W

B

/

R

L

/

B

G

/

L

Br

Y

L

/

Y

B

/

Y

G

B

G

/

Y

Dg

Ch

B

/

W

B

P

Y

/

R

Dg

Ch

B

/

W

B

P

Y

/

R

W

/

B

L

W

W

/

B

L

W

B

L

Ch

Y

Dg

L

Ch

B

Y

Dg

A

W

RE HARNESS

W

RE HARNESS

W

RE HARNESS

W

RE HARNESS

 SUB

W

RE

HARNESS2

Y

L

B

Y

L

B

W

RE HARNESS

 SUB

W

RE

HARNESS1

 SUB

W

RE

HARNESS2

 SUB

W

RE

HARNESS4

 SUB

W

RE

HARNESS3

(BLACK)

(BLACK)

B

C

D

Gy

Gy

R

B

R

Gy

R

Gy

R

B

/

R

G

B

W

Gy

W

Br

G

W

Gy

B

W

Br

(BLACK)

R

/

B

P

L

R

/

B

W

/

G

B

/

L

R

G

(BLACK)

R

B

R

B

W

G

P

L

Br

/

L

R

/

G

FUEL PUMP SYSTEM

7-64

3. Main switch
4. Main fuse
6. Battery
7. Fuel injection system fuse
11.Relay unit
13.Fuel pump relay
15.Diode 2
17.Fuel pump
27.ECU (electronic control unit)
68.Engine stop switch
77.Ignition fuse
81.ECU fuse

FUEL PUMP SYSTEM

7-65

EAS27570

TROUBLESHOOTING

If the fuel pump fails to operate.

NOTE:

• Before troubleshooting, remove the following part(s):
1. Rider seat
2. Tool kit tray
3. Rider seat bracket assembly
4. Left side cover
5. Headlight assembly

 

 NG

 →

OK

 ↓

 

 NG

 →

OK

 ↓

 

 NG

 →

OK

 ↓

 

 NG

 →

OK

 ↓

 

 NG

 →

OK

 ↓

 

 NG

 →

OK

 ↓

 

 NG

 →

OK

 ↓

1. Check the fuses.

(Main, fuel injection system, ignition 
and ECU)
Refer to “CHECKING THE FUS-
ES” on page 7-75.

Replace the fuse(s).

2. Check the battery.

Refer to “CHECKING AND 
CHARGING THE BATTERY” on 
page 7-76.

• Clean the battery terminals.
• Recharge or replace the battery.

3. Check the main switch.

Refer to “CHECKING THE 
SWITCHES” on page 7-71.

Replace the main switch.

4. Check the engine stop switch.

Refer to “CHECKING THE 
SWITCHES” on page 7-71.

The engine stop switch is faulty. Replace 
the right handlebar switch.

5. Check the relay unit (fuel pump re-

lay).
Refer to “CHECKING THE RE-
LAYS” on page 7-79.

Replace the relay unit.

6. Check the diode 2.

Refer to “CHECKING THE DI-
ODES” on page 7-81.

Replace the diode 2.

7. Check the fuel pump.

Refer to “CHECKING THE FUEL 
PUMP” on page 7-89.

Replace the fuel pump assembly.

FUEL PUMP SYSTEM

7-66

 

 NG

 →

OK

 ↓

8. Check the entire fuel pump system 

wiring.
Refer to “CIRCUIT DIAGRAM” on 
page 7-63.

Properly connect or repair the fuel pump 
system wiring.

Replace the ECU.

ELECTRICAL COMPONENTS

7-67

EAS27970

ELECTRICAL COMPONENTS

11

3

6

7

8

10

4

9

12

13

5

2

1

14

ELECTRICAL COMPONENTS

7-68

1. Cylinder-#2 right ignition coil
2. Cylinder-#2 left ignition coil
3. Fuel sender
4. Engine temperature sensor
5. Cylinder-#1 left ignition coil
6. Cylinder-#1 right ignition coil
7. ECU (electronic control unit)
8. EXUP servo motor
9. Speed sensor
10. Rectifier/regulator
11. Neutral switch
12. Horn 2
13. Horn 1
14. ISC (idle speed control) unit

ELECTRICAL COMPONENTS

7-69

16

18

2

11

13

9

8

10

12

14

15

17

1

3

4

5

6

7

ELECTRICAL COMPONENTS

7-70

1. Air temperature sensor
2. Main switch
3. Cylinder-#2 intake air pressure sensor
4. Throttle position sensor
5. Cylinder-#1 intake air pressure sensor
6. Fuse box
7. Starter relay
8. Fuel injection system fuse
9. Battery
10. Diode 2
11. Turn signal relay
12. Headlight relay
13. Relay unit
14. Diode 1
15. Main fuse
16. Lean angle cut-off switch
17. Crankshaft position sensor
18. Rear brake light switch

ELECTRICAL COMPONENTS

7-71

EAS27980

CHECKING THE SWITCHES

B

B

B

11

13

10

6

12

9

Y G

/

L G

B

P

Br

Y

R

/

W B

/

R

L

/

W W

/

B

R

Br

R Br L

/

Y L

/

B

ON

OFF

G

/

Y G

/

B

PUSH

Ch Br

/

W Dg B Y

/

R

(L)

(R)

(GRAY)

Dg

Ch

(GRAY)

B

B

G

/

Y G

/

B

(BLUE)

Y

G

G

/

L

(GRAY)

B

P

Y

/

R

Br

/

W

L

/

Y B

/

Y

B

B

(BLACK)

B

B

(BLACK)

8

7

(BLUE)

B

B

R

/

W B

/

R

G

/

L L

/

B

(BLACK)

W

/

B

L

/

W

2

3

5

4

(GRAY)

L

/

Y

L

/

B

1

L

/

B G

/

L

B

B

ELECTRICAL COMPONENTS

7-72

1. Main switch
2. Engine stop switch
3. Start switch
4. Accessory light switch
5. Front brake light switch
6. Neutral switch
7. Sidestand switch
8. Rear brake light switch
9. Clutch switch
10. Horn switch
11. Dimmer switch
12. Select switch
13. Turn signal switch

ELECTRICAL COMPONENTS

7-73

Check each switch for continuity with the pocket tester. If the continuity reading is incorrect, check the 
wiring connections and if necessary, replace the switch.

CAUTION:

ECA14370

Never insert the tester probes into the coupler terminal slots “a”. Always insert the probes from 
the opposite end of the coupler, taking care not to loosen or damage the leads.

NOTE:

• Before checking for continuity, set the pocket tester to “0” and to the “

Ω

 

×

 1” range.

• When checking for continuity, switch back and forth between the switch positions a few times.

The switches and their terminal connections are illustrated as in the following example of the main 
switch.
The switch positions “a” are shown in the far left column and the switch lead colors “b” are shown in the 
top row. 
The continuity (i. e., a closed circuit) between switch terminals at a given switch position is indicated by 
“

”. There is continuity between red and brown, blue/yellow and blue/black when the switch is 

set to “ON”.

 

Pocket tester

90890-03112

Analog pocket tester

YU-03112-C

R

Br

ON

OFF

R Br L

/

Y L/B

b

a

L

/

B L

/

Y

ELECTRICAL COMPONENTS

7-74

EAS27990

CHECKING THE BULBS AND BULB 
SOCKETS

NOTE:

Do not check any of the lights that use LEDs.

Check each bulb and bulb socket for damage or 
wear, proper connections, and also for continuity 
between the terminals.
Damage/wear 

→

 Repair or replace the bulb, 

bulb socket or both.
Improperly connected 

→

 Properly connect.

No continuity 

→

 Repair or replace the bulb, bulb 

socket or both.

Types of bulbs

The bulbs used on this vehicle are shown in the 
illustration.
• Bulbs “a” and “b” are used for the headlights 

and usually use a bulb holder that must be de-
tached before removing the bulb. The majority 
of these types of bulbs can be removed from 
their respective socket by turning them coun-
terclockwise.

• Bulbs “c” are used for turn signal and tail/brake 

lights and can be removed from the socket by 
pushing and turning the bulb counterclockwise.

• Bulbs “d” and “e” are used for meter and indi-

cator lights and can be removed from their re-
spective socket by carefully pulling them out.

Checking the condition of the bulbs

The following procedure applies to all of the 
bulbs.

1. Remove:

• Bulb

WARNING

EW1D71009

Since headlight bulbs get extremely hot, 
keep flammable products and your hands 
away from them until they have cooled 
down.

CAUTION:

EC1D71006

• Be sure to hold the socket firmly when re-

moving the bulb. Never pull the lead, other-
wise it may be pulled out of the terminal in 
the coupler.

• Avoid touching the glass part of a headlight 

bulb to keep it free from oil, otherwise the 
transparency of the glass, the life of the 
bulb, and the luminous flux will be adverse-
ly affected. If the headlight bulb gets soiled, 
thoroughly clean it with a cloth moistened 
with alcohol or lacquer thinner.

2. Check:

• Bulb (for continuity)

(with the pocket tester)
No continuity 

→

 Replace.

NOTE:

Before checking for continuity, set the pocket 
tester to “0” and to the “

Ω

 

×

 1” range.

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a. Connect the positive tester probe to terminal 

“1” and the negative tester probe to terminal 
“2”, and check the continuity.

b. Connect the positive tester probe to terminal 

“1” and the negative tester probe to terminal 
“3”, and check the continuity.

c. If either of the readings indicate no continuity, 

replace the bulb.

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Pocket tester

90890-03112

Analog pocket tester

YU-03112-C

ELECTRICAL COMPONENTS

7-75

Checking the condition of the bulb sockets

The following procedure applies to all of the bulb 
sockets.
1. Check:

• Bulb socket (for continuity)

(with the pocket tester)
No continuity 

→

 Replace.

NOTE:

Check each bulb socket for continuity in the 
same manner as described in the bulb section; 
however, note the following.

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a. Install a good bulb into the bulb socket.
b. Connect the pocket tester probes to the re-

spective leads of the bulb socket.

c. Check the bulb socket for continuity. If any of 

the readings indicate no continuity, replace 
the bulb socket.

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EAS28000

CHECKING THE FUSES

The following procedure applies to all of the fus-
es.

CAUTION:

EC1D71019

To avoid a short circuit, always turn the main 
switch to “OFF” when checking or replacing 
a fuse.

1. Remove:

• Rider seat

Refer to “GENERAL CHASSIS” on page 4-1.

2. Check:

• Fuse

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a. Connect the pocket tester to the fuse and 

check the continuity.

NOTE:

Set the pocket tester selector to “

Ω

 

×

 1”.

b. If the pocket tester indicates “

∞

”, replace the 

fuse.

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3. Replace:

• Blown fuse

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a. Turn the main switch to “OFF”.
b. Install a new fuse of the correct amperage 

rating.

c. Set on the switches to verify if the electrical 

circuit is operational.

d. If the fuse immediately blows again, check 

the electrical circuit.

WARNING

EWA13310

Never use a fuse with an amperage rating 
other than that specified. Improvising or us-
ing a fuse with the wrong amperage rating 
may cause extensive damage to the electri-

 

Pocket tester

90890-03112

Analog pocket tester

YU-03112-C

 

Pocket tester

90890-03112

Analog pocket tester

YU-03112-C

Fuses

Amperage 

rating

Q’ty

Main

50 A

1

Ignition

25 A

1

Headlight

20 A

1

Fuel injection system

15 A

1

Signaling system

10 A

1

Taillight

10 A

1

ECU

10 A

1

Backup (odometer and 

clock)

10 A

1

Auxiliary DC connector

3 A

1

Spare

25 A

1

Spare

20 A

1

Spare

15 A

1

Spare

10 A

1

Spare

3 A

1