Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 71

7-14

FI

FUEL INJECTION SYSTEM

Fault code No.

13

Symptom

Intake air pressure sensor 1 (cylinders #1, #2, and #3): open or short circuit 
detected.

 Diagnostic code No. 03 (intake air pressure sensor 1 (cylinders #1, #2, and #3))

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Intake air pressure sensor 1 (cylin-
ders #1, #2, and #3) coupler
Wire harness ECU coupler
Fuel injection system sub-wire har-
ness coupler

Check the couplers for any pins that may have 
pulled out.
Check the locking condition of the couplers.
If there is a malfunction, repair it and connect the 
coupler securely.

Setting the 
engine stop 
switch to “RUN” 
and turning the 
main switch on.

2

Open or short circuit in wire harness 
and/or fuel injection system sub-wire 
harness.

Repair or replace if there is an open or short cir-
cuit.
Between the intake air pressure sensor 1 (cylin-
ders #1, #2, and #3) coupler and ECU coupler.

Pink/White – Pink/White
Black/Blue – Black/Blue
Blue – Blue

3

Defective intake air pressure sensor 1 
(cylinders #1, #2, and #3).

Execute the diagnostic mode (code No. 03).
Replace if defective.
1. Connect the pocket tester (DC 20 V) to the 

intake air pressure sensor 1 (cylinders #1, #2, 
and #3) coupler terminals as shown.

2. Turn the main switch on.
3. Measure the intake air pressure sensor 1 (cyl-

inders #1, #2, and #3) output voltage.

4. Is the intake air pressure sensor 1 (cylinders 

#1, #2, and #3) OK?

Positive tester probe 

→ Pink/White 1 

Negative tester probe 

→ Black/Blue 2 

L

P/W B/L

1

2

Intake air pressure sensor 1 (cylin-
ders #1, #2, and #3) output volt-
age:

3.75 ~ 4.25 V

7-15

FI

FUEL INJECTION SYSTEM

Fault code No.

14

Symptom

Intake air pressure sensor 1 (cylinders #1, #2, and #3): hose system mal-
function (clogged or detached hose).

Diagnostic code No. 03 (intake air pressure sensor 1 (cylinders #1, #2, and #3))

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Intake air pressure sensor 1 (cylinders 
#1, #2, and #3) hoses are detached, 
clogged, kinked, or pinched.

Repair or replace the intake air pressure sensor 1 
(cylinders #1, #2, and #3) hoses.

Starting the 
engine and 
operating it at 
idle.

2

Intake air pressure sensor 1 (cylinders 
#1, #2, and #3) malfunction at intermedi-
ate electrical potential.

Check and repair the connection.
Replace it if there is a malfunction.

3

Connections
Intake air pressure sensor 1 (cylinders 
#1, #2, and #3) coupler
Wire harness ECU coupler

Check the couplers for any pins that may have 
pulled out.
Check the locking condition of the couplers.
If there is a malfunction, repair it and connect the 
coupler securely.

4

Defective intake air pressure sensor 1 
(cylinders #1, #2, and #3).

Execute the diagnostic mode (code No. 03).
Replace if defective.
Refer to “Fault code No. 13”.

Fault code No.

15

Symptom

Throttle position sensor: open or short circuit detected.

Diagnostic code No. 01 (throttle position sensor)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Installed condition of throttle position 
sensor.

Check for looseness or pinching. 
Check that it is installed in the specified position. 
Refer to “THROTTLE BODY”.

Setting the 
engine stop 
switch to “RUN” 
and turning the 
main switch on.

2

Connections

Throttle position sensor coupler 
Wire harness ECU coupler
Fuel injection system sub-wire har-
ness coupler

Check the couplers for any pins that may have 
pulled out.
Check the locking condition of the couplers.
If there is a malfunction, repair it and connect the 
coupler securely.

3

Open or short circuit in wire harness 
and/or fuel injection system sub-wire 
harness.

Repair or replace if there is an open or short cir-
cuit. 
Between the throttle position sensor coupler and 
ECU coupler.

Black/Blue – Black/Blue 
Yellow – Yellow 
Blue – Blue

4

Throttle position sensor lead open circuit 
output voltage check.

Check for open circuit and replace the throttle 
position sensor.

Black/Blue – Yellow

Open circuit item

Output voltage 

Ground wire open cir-
cuit 

5 V

Output wire open circuit  0 V

Power supply wire 
open circuit

0 V

5

Defective throttle position sensor.

Execute the diagnostic mode (code No. 01).
Replace if defective.
Refer to “THROTTLE BODY”.

7-16

FI

FUEL INJECTION SYSTEM

Fault code No.

16

Symptom

Stuck throttle position sensor detected.

Diagnostic code No. 01 (throttle position sensor)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Installed condition of throttle position 
sensor.

Check for looseness or pinching. 
Check that it is installed in the specified position. 
Refer to “THROTTLE BODY”.

Starting the 
engine, operat-
ing it at idle, and 
then racing it.

2

Defective throttle position sensor.

Execute the diagnostic mode (code No. 01). 
Replace if defective.
Refer to “THROTTLE BODY”.

Fault code No.

21

Symptom

Coolant temperature sensor: open or short circuit detected.

Diagnostic code No. 06 (coolant temperature sensor)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Coolant temperature sensor coupler
Wire harness ECU coupler
Coolant temperature sensor sub-lead 
coupler

Check the couplers for any pins that may have 
pulled out.
Check the locking condition of the couplers.
If there is a malfunction, repair it and connect the 
coupler securely.

Setting the 
engine stop 
switch to “RUN” 
and turning the 
main switch on.

2

Open or short circuit in wire harness 
and/or coolant temperature sensor sub-
lead coupler.

Repair or replace if there is an open or short cir-
cuit.
Between the coolant temperature sensor coupler 
and ECU coupler.

Black/Blue – Black/Blue
Green/White – Green/White 

3

Defective coolant temperature sensor.

Execute the diagnostic mode (code No. 06). 
Replace if defective.
Refer to “SIGNAL SYSTEM” in CHAPTER 8.

Fault code No.

22

Symptom

Intake air temperature sensor: open or short circuit detected.

Diagnostic code No. 05 (intake air temperature sensor)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Intake air temperature sensor coupler
Wire harness ECU coupler

Check the couplers for any pins that may have 
pulled out.
Check the locking condition of the couplers.
If there is a malfunction, repair it and connect the 
coupler securely.

Setting the 
engine stop 
switch to “RUN” 
and turning the 
main switch on.

2

Open or short circuit in wire harness.

Repair or replace if there is an open or short cir-
cuit.
Between the intake air temperature sensor cou-
pler and ECU coupler.

Black/Blue – Black/Blue
Brown/White – Brown/White

3

Defective intake air temperature sensor.

Execute the diagnostic mode (code No. 05).
Replace if defective.
Refer to “INTAKE AIR TEMPERATURE SEN-
SOR”.

7-17

FI

FUEL INJECTION SYSTEM

Fault code No.

25

Symptom

Intake air pressure sensor 2 (cylinder #1): open or short circuit detected.

Diagnostic code No. 04 (intake air pressure sensor 2 (cylinder #1))

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Intake air pressure sensor 2 (cylinder 
#1) coupler
Wire harness ECU coupler
Fuel injection system sub-wire har-
ness coupler

Check the couplers for any pins that may have 
pulled out.
Check the locking condition of the couplers.
If there is a malfunction, repair it and connect the 
coupler securely.

Setting the 
engine stop 
switch to “RUN” 
and turning the 
main switch on.

2

Open or short circuit in wire harness 
and/or fuel injection system sub-wire 
harness.

Repair or replace if there is an open or short cir-
cuit.
Between the intake air pressure sensor 2 (cylin-
der #1) coupler and ECU coupler.

Pink/Black – Pink/Black
Black/Blue – Black/Blue
Blue – Blue

3

Defective intake air pressure sensor 2 
(cylinder #1).

Execute the diagnostic mode (code No. 04).
Replace if defective.
1. Connect the pocket tester (DC 20 V) to the 

intake air pressure sensor 2 (cylinder #1) cou-
pler terminals as shown.

2. Turn the main switch on.
3. Measure the intake air pressure sensor 2 (cyl-

inder #1) output voltage.

4. Is the intake air pressure sensor 2 (cylinder 

#1) OK?

Positive tester probe 

→ Pink/Black 1 

Negative tester probe 

→ Black/Blue 2 

L

P/B B/L

1

2

Intake air pressure sensor 2 (cylin-
der #1) output voltage:

3.75 ~ 4.25 V