Snowmobile Yamaha Phazer PZ50W, PZ50GTW, PZ50FXW, PZ50MW, PZ50VTW, PZ50MPW. Manual - part 70

7-26

FI

FUEL INJECTION SYSTEM

Fault code No.

85

Symptom

Oil pressure switch: open circuit detected.

Diagnostic code No. – –

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Oil pressure switch 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 circuit in wire harness.

Repair or replace if there is an open circuit.
Between oil pressure switch coupler and ECU 
coupler.

Yellow/Green – Yellow/Green

3

Defective oil pressure switch.

With the engine stopped, check that there is con-
tinuity between the oil pressure switch terminals 
and oil pressure switch body metal components.

Fault code No.

88

Symptom

Drive position switch: short circuit detected.
Reverse position switch: short circuit detected.

Diagnostic code No. – –

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Installed condition of switch

Check for looseness or pinching.

Starting the 
engine and 
operating it at 
idle.

2

Connections

Drive position switch connector
Reverse position switch connector
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

Short circuit in wire harness and/or gear 
motor sub-wire harness.

Repair or replace if there is an short circuit.
Between drive position switch connector and 
ECU coupler.

White/Blue – White/Blue

Between reverse position switch connector and 
ECU coupler.

White/Red – White/Red

4

Defective drive position switch and/or 
reverse position switch.

Replace if defective.
Refer to “DRIVE POSITION SWITCH AND 
REVERSE POSITION SWITCH (PZ50GT/
PZ50FX/PZ50M/PZ50VT/PZ50MP)” in CHAP-
TER 8.

7-27

FI

FUEL INJECTION SYSTEM

Fault code No.

Er-1

Symptom

No signals are received from the ECU.

Er-2

Symptom

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

Er-3

Symptom

Data from the ECU cannot be received correctly.

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

Wire harness ECU coupler

Check the coupler for any pins that may have 
pulled out.
Check the locking condition of the coupler.
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 speedometer unit coupler and ECU 
coupler.

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

3

Malfunction in speedometer unit.

Replace the speedometer unit.

4

Malfunction in ECU.

Replace the ECU.

7-28

FI

FUEL INJECTION SYSTEM

OIL PRESSURE SWITCH

1. Disconnect:

• Oil pressure switch coupler 1 

2. Connect:

• Pocket tester

(between the engine ground and oil pressure
switch terminal)

1

3. Check:

• Oil pressure switch continuity

No continuity 

→ Replace the oil pressure

switch.

INTAKE AIR TEMPERATURE SENSOR

1. Remove the intake air temperature sensor.

CAUTION:

Handle the intake air temperature sensor with
special care. Never subject it to shock or allow
it to be dropped. If it is dropped, it must be
replaced.

2. Connect:

• Pocket tester

(to the intake temperature sensor)

NOTE:

Set the tester selector to the “

Ω × 100” position.

3. Immerse the intake temperature sensor 1 in

water 2 and check the intake temperature sen-
sor operation.

3 Temperature gauge

CAUTION:

Never heat the water to a temperature of 120 °C
(248 °F) or more.

4. If the intake air temperature sensor operation is

defective, replace it.

5. Install the intake air temperature sensor and

connect the intake air temperature sensor cou-
pler.

Intake temperature sensor resis-
tance:

290 ~ 390 

Ω at 80 °C (176 °F)

3

1

2

7-29

FI

THROTTLE BODY

THROTTLE BODY

Order

Job name/Part name

Q’ty

Remarks

Throttle body removal

Remove the parts in the order listed below.

Air filter case assembly

Refer to “COWLINGS” in CHAPTER 3.

1

Throttle position sensor coupler

1

Disconnect.

2

Fuel hose

2

3

Fuel return hose

1

Disconnect.

4

Idle adjusting screw

1

5

Throttle cable

1

6

Plastic band

1

7

Throttle body heater inlet hose

1

8

Throttle body assembly

1

9

Throttle body heater outlet hose

1

Disconnect.

10

Injector coupler

2

Disconnect.

11

Throttle body joint

2

For installation, reverse the removal proce-
dure.

11

10

5

6

7

8

4

1

3

2

9

10