Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 72

7-18

FI

FUEL INJECTION SYSTEM

Fault code No.

26

Symptom

Intake air pressure sensor 2 (cylinder #1): hose system malfunction 
(clogged or detached hose).

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

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Intake air pressure sensor 2 (cylinder #1) 
hose is detached, clogged, kinked, or 
pinched.

Repair or replace the intake air pressure sensor 2 
(cylinder #1) hose.

Starting the 
engine and 
operating it at 
idle.

2

Intake air pressure sensor 2 (cylinder #1) 
malfunction at intermediate electrical 
potential.

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

3

Connections
Intake air pressure sensor 2 (cylinder #1) 
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 2 
(cylinder #1).

Execute the diagnostic mode (code No. 04). 
Replace if defective.
Refer to “Fault code No. 25”.

Fault code No.

30

Symptom

Engine stops when an oil pressure drop is detected.

Diagnostic code No. – –

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Oil pressure dropped.

Place the snowmobile on a level surface, and 
then check the oil pressure after warming up the 
engine.
Refer to “ENGINE OIL REPLACEMENT” in 
CHAPTER 2.

Starting the 
engine and 
operating it at 
idle.

2

Short circuit in oil pressure switch lead.
Short circuit in oil pressure switch sub-
lead.

Disconnect the ECU coupler, and then use the 
circuit tester to check for continuity between the 
engine ground and the oil pressure switch cou-
pler (yellow/green).
Repair or replace if there is no continuity.

3

Defective oil pressure switch.

Start the engine, warm it up for 1 minute, and 
then use the circuit tester to check for continuity 
between the oil pressure switch coupler (yellow/
green) and the switch body.
Replace if there is continuity.

7-19

FI

FUEL INJECTION SYSTEM

Fault code No.

33

Symptom

Malfunction detected in the primary lead of the cylinder-#1 ignition coil.

Diagnostic code No. 30 (cylinder-#1 ignition coil)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Cylinder-#1 ignition coil coupler
Wire harness ECU couplers

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.

Starting the 
engine and 
operating it at 
idle.

2

Open or short circuit in wire harness.

Repair or replace if there is an open or short cir-
cuit.
Between the cylinder-#1 ignition coil coupler and 
ECU couplers.

Orange – Orange
Red/White – Red/White

3

Detective cylinder-#1 ignition coil.

Execute the diagnostic mode (code No. 30).
Test the primary and secondary coils for continu-
ity.
Replace if defective.
Refer to “IGNITION SYSTEM” in CHAPTER 8.

Fault code No.

34

Symptom

Malfunction detected in the primary lead of the cylinder-#2 ignition coil.

Diagnostic code No. 31 (cylinder-#2 ignition coil)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Cylinder-#2 ignition coil coupler
Wire harness ECU couplers

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.

Starting the 
engine and 
operating it at 
idle.

2

Open or short circuit in wire harness.

Repair or replace if there is an open or short cir-
cuit.
Between the cylinder-#2 ignition coil coupler and 
ECU couplers.

Gray/Red – Gray/Red
Red/White – Red/White

3

Defective cylinder-#2 ignition coil.

Execute the diagnostic mode (code No. 31).
Test the primary and secondary coils for continu-
ity.
Replace if defective.
Refer to “IGNITION SYSTEM” in CHAPTER 8.

7-20

FI

FUEL INJECTION SYSTEM

Fault code No.

35

Symptom

Malfunction detected in the primary lead of the cylinder-#3 ignition coil.

Diagnostic code No. 32 (cylinder-#3 ignition coil)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Cylinder-#3 ignition coil coupler
Wire harness ECU couplers

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.

Starting the 
engine and 
operating it at 
idle.

2

Open or short circuit in wire harness.

Repair or replace if there is an open or short cir-
cuit.
Between the cylinder-#3 ignition coil coupler and 
ECU couplers.

Orange/Green – Orange/Green
Red/White – Red/White

3

Detective cylinder-#3 ignition coil.

Execute the diagnostic mode (code No. 32).
Test the primary and secondary coils for continu-
ity.
Replace if defective.
Refer to “IGNITION SYSTEM” in CHAPTER 8.

Fault code No.

37

Symptom

Engine speed is high when the engine is idling.

Diagnostic code No. 54 (ISC (idle speed control) unit)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Throttle valve does not fully close.

Check the throttle body.
Refer to “THROTTLE BODY”.
Check the throttle cable.
Refer to “THROTTLE CABLE FREE PLAY 
ADJUSTMENT” in CHAPTER 2. 

ISC valve returns to 
its original position 
by setting the 
engine stop switch 
to “RUN” and turn-
ing the main switch 
on and off.
Reinstated if the 
engine idle speed is 
within specification 
after starting the 
engine.

2

ISC valve is stuck fully open due to discon-
nected ISC unit 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.)

Check that the ISC unit coupler is not dis-
connected.
The ISC valve is stuck fully open if it does 
not operate when turning the main switch 
off.
(Touch the ISC unit with your hand and 
check if it is vibrating to confirm if the ISC 
valve is operating.)

NOTE:

Do not remove the ISC unit.

3

ISC valve is not moving correctly.

Execute the diagnostic mode (code 
No. 54).
After the ISC valve is fully closed, it opens 
to the standby opening position. This oper-
ation takes approximately 12 seconds. 
Start the engine. If the error recurs, 
replace the throttle body assembly.

7-21

FI

FUEL INJECTION SYSTEM

Fault code No.

42

Symptom

No normal signals are received from the speed sensor.

Diagnostic code No. 07 (speed sensor)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Speed 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.

Starting the 
engine, and 
inputting the 
snowmobile 
speed signals 
by operating the 
snowmobile at a 
low speed of 20 
to 30 km/h.

2

Open or short circuit in wire harness.

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

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

3

Defective speed sensor.

Execute the diagnostic mode (code No. 07). 
Replace if defective.
Refer to “SIGNAL SYSTEM” in CHAPTER 8.

4

Gear for detecting snowmobile speed 
has broken.

Replace if defective.
Refer to “FRONT AXLE AND TRACK” in CHAP-
TER 4.