Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 73

7-22

FI

FUEL INJECTION SYSTEM

Fault code No.

43

Symptom

Power supply to the fuel injectors and fuel pump is not normal.

Diagnostic code No. 09 (fuel system voltage)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Connections

Fuel injection system relay 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.

Repair or replace if there is an open or short cir-
cuit.
Between the fuel injection system relay coupler 
and ECU coupler.

Blue/Red – Blue/Red

Between the fuel injection system relay coupler 
and engine stop switch coupler.

Red/White – Red/White

Between the engine stop switch coupler and main 
switch coupler.

Brown – Brown

3

Malfunction or open circuit in fuel injec-
tion system relay.

Execute the diagnostic mode (code No. 09). 
Replace if defective.

NOTE:

When the leads are disconnected, the voltage 
check by the code No. 09 is impossible.

1. Disconnect the fuel injection system relay from 

the wire harness and remove it.

2. Connect the pocket tester (

Ω × 1) and battery 

(12 V) to the fuel injection system relay termi-
nals as shown.

3. Does the fuel injection system relay have con-

tinuity between the red/green and red/blue ter-
minals?

Positive battery terminal 

→ Red/White 1 

Negative battery terminal 

→ Blue/Red 2 

Positive tester probe 

→ Red/Green 3 

Negative tester probe 

→ Red/Blue 4 

7-23

FI

FUEL INJECTION SYSTEM

Fault code No.

44

Symptom

Error is detected while reading or writing on EEPROM (CO adjustment 
value).

Diagnostic No. 60 (EEPROM improper cylinder indication)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Malfunction in ECU.

Execute the diagnostic mode (code No. 60).
1. Check the faulty cylinder. (If multiple cylinders 

are defective, the display alternates every 2 
seconds.)

2. Readjust the CO of the displayed cylinder.
Replace ECU if defective.

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

Fault code No.

46

Symptom

Power supply to the ECU is not normal.

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.

Starting the 
engine and 
operating it at 
idle.

2

Faulty battery.

Replace or charge the battery.
Refer to “BATTERY INSPECTION” in CHAPTER 
2.

3

Malfunction in rectifier/regulator.

Replace if defective.
Refer to “CHARGING SYSTEM” in CHAPTER 8.

4

Open or short circuit in wire harness.

Repair or replace if there is an open or short cir-
cuit.
Between the battery and main fuse.

Red – Red

Between the main fuse and ignition fuse.

Red – Red

Between the ignition fuse and main switch cou-
pler.

Red/Yellow – Red/Yellow

Between the main switch coupler and engine stop 
switch coupler.

Brown – Brown

Between the engine stop switch coupler and ECU 
coupler.

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.

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

7-24

FI

FUEL INJECTION SYSTEM

Fault code No.

81

Symptom

Grip warmer: open or short circuit detected.

Diagnostic code No. 26 (grip warmer operation)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Open or short circuit in wire harness.

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

Yellow/Red-Yellow/Red

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

Fault code No.

83

Symptom

Thumb warmer: short circuit detected.

Diagnostic code No. 27 (thumb warmer operation)

Order

Item/components and probable cause

Check or maintenance job

Reinstatement 
method

1

Short circuit in wire harness.

Repair or replace if there is a short circuit. 
Between the thumb warmer coupler and ECU 
coupler.

Light green-Light green

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

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
Oil pressure switch 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.

Starting the 
engine and 
operating it at 
idle.

2

Open circuit in wire harness and/or oil 
pressure switch sub-lead.

Repair or replace if there is an open circuit.
Between the 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 
or engine ground.
Replace if there is no continuity.
Refer to “OIL PRESSURE SWITCH”.

7-25

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 signal time.

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
Speedometer unit sub-lead 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.

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

2

Open or short circuit in wire harness 
and/or speedometer unit sub-lead.

Repair or replace if there is an open or short cir-
cuit.
Between speedometer unit coupler and ECU 
coupler.

Blue/Yellow – Blue/Yellow

3

Malfunction in speedometer unit.

Replace the speedometer unit.

4

Malfunction in ECU.

Replace the ECU.