Snowmobile Yamaha Phazer PZ50W, PZ50GTW, PZ50FXW, PZ50MW, PZ50VTW, PZ50MPW. Manual - part 68

7-18

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
Sub-wire harness 2 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.

Turning the 
main switch on.

2

Open or short circuit in wire harness 
and/or sub-wire harness 2.

Repair or replace if there is an open or short cir-
cuit.
Between 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.

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 intake air temperature sensor coupler 
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”.

7-19

FI

FUEL INJECTION SYSTEM

Fault code No.

25

Symptom

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

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

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Cylinder-#2 intake air pressure sen-
sor 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.

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 cylinder-#2 intake air pressure sensor 
coupler and ECU coupler.

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

3

Defective cylinder-#2 intake air pressure 
sensor.

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

inder-#2 intake air pressure sensor coupler 
terminals as shown.

2. Turn the main switch on.
3. Measure the cylinder-#2 intake air pressure 

sensor output voltage.

4. Is the cylinder-#2 intake air pressure sensor 

OK?

Positive tester probe 

→ Pink 1 

Negative tester probe 

→ Black/Blue 2 

Cylinder-#2 intake air pressure 
sensor output voltage:

2.55 ~ 4.25 V

7-20

FI

FUEL INJECTION SYSTEM

Fault code No.

26

Symptom

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

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

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Cylinder-#2 intake air pressure sensor 
hose is detached, clogged, kinked, or 
pinched.
Cylinder-#2 intake air pressure sensor 
malfunction at intermediate electrical 
potential.

Repair or replace the sensor hose.
Inspect and repair the connection.

Starting the 
engine and 
operating it at 
idle.

2

Connections
Cylinder-#2 intake air pressure 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.

3

Defective cylinder-#2 intake air pressure 
sensor.

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.

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.

7-21

FI

FUEL INJECTION SYSTEM

Fault code No.

33

Symptom

Open circuit 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 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 
operating it at 
idle.

2

Open or short circuit in wire harness 
and/or sub-wire harness 1.

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

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

Open circuit 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 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 
operating it at 
idle.

2

Open or short circuit in wire harness 
and/or sub-wire harness 1.

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

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.