CFMoto motorcycle CF650NK. Service Manual - part 15

FUEL SYSTEM (EFI) 3-33

Self-diagnosis Procedures
Note:

o 

If all the parts and circuits checked out  good, be sure to check the ECU for ground and power supply. If the

   ground and power supply are checked good, replace the ECU.

o 

When no trouble code is displayed, the electrical parts of the EFI system has no fault, and the mechanical

   parts of the EFI system and the engine are suspect.

o 

If FI indicator light keeps on for 10 seconds and turns off, then shortly blinks 15 times. This alerts the owner

   to maintain the EFI system. The first maintenance should be done after  the ECU has been worked for 50

   hours. Then every 100 hours, do a maintenance.

3-34 FUEL SYSTEM (EFI)

Self-diagnosis Procedures

Backups

○

 The ECU takes the following measures to prevent engine damage when the EFI or the ignition system 

   parts have troubles.

Trouble Codes

Parts

Output Signal Unstable 
Range or Criteria

Backups by ECU

5 or 6

Inlet Air Temp Sensor

Inlet Air Temp
Ta=-30

O

C~+130

O

C

If the inlet air tem sensor 
fails(the signal is out of the 
usable range, wiring short 
or open), the ECU sets Ta at 
20

O

C.

3 or 4

Coolant Temp Sensor

Water Temp Sensor
Tw=-30

O

C~+130

O

C

If the water temp sensor 
system fails(the signal is out 
of the usable range, wiring 
short or open), the ECU sets 
Tw at 45

O

C.

50

Roll-over Sensor

Roll-over Sensor Output 
Resistance R=62k

Ω

 or R=0

Ω

If roll-over sensor has this 
failure, the ECU shuts off the 
fuel pump, the fuel injectors 
and the ignition system.

47

Oxygen Sensor #1

The oxygen sensor is active 
a n d   s e n s o r   m u s t   s e n d 
signals (output voltage) 
continuously to the ECU.

If the oxygen sensor is not 
activated, the ECU stops 
oxygen sensor feedback 
mode.

48

Oxygen Sensor #2

The oxygen sensor is active 
a n d   s e n s o r   m u s t   s e n d 
signals (output voltage) 
continuously to the ECU.

If the oxygen sensor is not 
activated, the ECU stops 
oxygen sensor feedback 
mode.

FUEL SYSTEM (EFI) 3-35

Throttle Position Sensor

Throttle Position Sensor Removal/Adjustment

Throttle Position Sensor Input Voltage Inspection

NOTE

○

 Be sure the battery is fully charged.



 Turn the ignition switch OFF.



 Disconnect the throttle position sensor connector

   and connect the harness adapter [A] between these
   connectors.



 Connect a digital meter to the harness adapter lead.



 Measure the sensor input voltage with the engine

   stopped and with the connector joined.



 Turn the ignition switch ON.

   Throttle Position Sensor Input Voltage

   Connections to Adapter

   Meter (+)

Gr/R (C)

   Meter (-) 

 L/G (D)

   Standard: 4.75   5.25 V DC



 Turn the ignition switch OFF.

If the input voltage is normal, check the sensor out-

   put voltage.

If the input voltage is less than the standard, re-

   move the ECU and check the wiring between these
   connectors.

○

Disconnect the ECU and sensor connectors.

N

O

I

T

U

A

C

Do not remove or adjust the throttle position

sensor [A] since it has been adjusted and set

with precision at the factory.

Never drop the throttle body assy, especially

on a hard surface. Such a shock to the sensor

can damage it.

3-36 FUEL SYSTEM (EFI)



Turn the ignition switch OFF.



Disconnect ECU connector and throttle position

    sensor connector.



Test the continuity of the 2 lead wires.

ECU Connector [A] 

 Throttle Body Connec-

    tor [B]

   Throttle Body Connector

 (ECU terminal 32)

   Throttle Body Connector

 (ECU terminal 27)

   Standard: 0

 



If the wiring is good, check the ECU for its ground

  and power supply (see ECU Power Supply

   Inspection).

Throttle Position Sensor
Wiring Connection

Main Throttle Sensor Output Voltage Inspection



 Measure the output voltage at the main throttle

  sensor in the same way as input voltage
    inspection, Note the following.



 Disconnect the main throttle sensor connector

   and connect the harness adapter [A] between
    these connectors.



  Start the engine and warm it up thoroughly.



  Check idle speed to ensure the throttle opening

    is correct.

       Idle Speed

Standard: 1 300

130 r/min (rpm)



If the idle speed is out of the specified range, adjust

   it (Inspect throttle cable and EFI system).



Turn the ignition switch OFF.



Measure the output voltage of the sensor with the

engine stopped, and with the connector joined.



Turn the ignition switch ON.

FUEL SYSTEM (EFI) 3-37

Throttle Position Sensor



If the output voltage is out of the standard, inspect

 the main throttle sensor resistance.



If the output voltage is normal, check the wiring for

    continuity.

Wiring Connection



Turn the ignition switch OFF.



Disconnect ECU connector and throttle position

    sensor connector.



Test the continuity of the lead wires.

    

ECU Connector [A]

Throttle Body Con

    nector [B]

    Thrrottle Body Connector Br/R

(ECU termi-

    nal 30)

  Thrrottle Body Connector 

(ECU

    terminal 27)

    Standard: 0

 



If the wiring is good, check the ECU for its ground

  and power supply (see ECU Power Supply
   Inspection).

Throttle Position Sensor Output Voltage

Connections  to Adapter
Meter (+)   Br/R (sensor output) lead
Meter (-) 

L/G(sensor ground) lead

Standard:

0.4~0.7 V DC (at idle throttle opening)
2.9~3.4 V DC (at full throttle opening)

3-38 FUEL SYSTEM (EFI)

Throttle Position Sensor
Throttle Position Sensor Resistance Inspection



 Turn the ignition switch OFF.



 Disconnect ECU connector and throttle position

    sensor connector.



 Connect a hand tester [A] to the throttle position

   sensor connector [B].



 Measure the throttle position sensor resistance.

Main Throttle Sensor Resistance

Connections: Gr/R lead [C]

 Br/R lead [D]

Standard:

1.1~1.4 k



If the reading is out of the range, replace the throttle

   body assy.



If the reading is within the range, but the problem

   still exists, replace the ECU (see ECU Removal/
   Installation).

1.  ECU                           2.  TPS

Throttle Position Sensor Calibration



Calibrate the TPS using a PDA(see PDA section)

FUEL SYSTEM (EFI) 3-39

Inlet Air Pressure Sensor

Inlet Air Pressure Sensor Removal



 Remove fuel tank(see Fuel Tank Removal).



 Disconnect the inlet air pressure sensor connector [A].



 Remove screws [B].



 Pull up the inlet air pressure sensor [C].

Inlet Air Pressure Sensor Installation



 Place inlet air pressure sensor on the air filter housing.



 Securely tighten screws [B].

Inlet Air Pressure Sensor Input Voltage Inspec-

tion

 

NOTE

Be sure the battery is fully charged.

The output voltage varies with the temperature

    change.



 Remove the ECU (see ECU Removal). Do not dis-

   connect the ECU connectors.



Connect a hand tester to the connector

   with the needle adapter set.



 Measure the

 

input voltage with the engine stopped,

   and with the connectors joined.



Turn the ignition switch ON.

    Inlet Air Pressure Sensor Input Voltage

    Connections  to ECU

    Meter (+)

W/Br lead(ECU terminal 28)

    Meter(-)

L/G lead (terminal 27)

    Standard: 2.5

~3.5V DC when inlet air tempera-

    ture is 20 

o

C



 Turn the ignition switch off.



 If the reading is within the standard range, check

   the sensor output voltage.



 If the reading is less than the standard range, re

   move the ECU and check the wiring between these
   connectors.



 If the wiring is good, check the ECU for its ground

  and power supply (see ECU Power Supply
   Inspection).

N

O

I

T

U

A

C

Never drop the sensor, especially on a hard

surface. Such a shock to the part can damage it.

3-40 FUEL SYSTEM (EFI)

Inlet Air Temperature Sensor

Inlet Air Temperature Sensor Resistance 
Inspection

●

 Remove the inlet air temperature sensor (see In-

   let Air Temperature Sensor Removal/Installation).

●

 Suspend the sensor [A] in a container of machine 

   oil so that the heat-sensitive portion issubmerged.

●

 Suspend a thermometer [B] with the heat-

   sensitive portion [C] located in almost the same  
    depth with the sensor.

NOTE

○

 

The sensor and thermometer must not touch the 

    container side or bottom.

●

 Place the container over a source of heat and 

   gradually raise the temperature of the oil while 
    stirring the oil gently for even temperature.

●

 Using a hand tester, measure the internal resis-

   tance of the sensor across the terminals at the 
    temperatures shown in the table.

Inlet Air Temperature  Sensor Resistance
Standard:   8.4~9.4 k       (0 

O

C)

                   2.3~2.6 k 

Ω

 (30 

0

C)

If the measurement is out of the range, replace 

   the sensor.

T (

O

C) Upper Limit

Middle Data Lower Limit

-10

13887.17

14618.07

15348.98

-5

10798.63

11366.98

11935.33

0

8474.68

8920.71

9366.75

5

6709.06

7062.17

7415.27

10

5355.29

5637.15

5919.01

15

4308.25

4535.00

4761.76

20

3491.75

3675.52

3859.30

22

3216.66

3385.96

3555.25

24

2966.52

3122.65

3278.78

26

2738.79

2882.94

3027.09

28

2531.23

2664.65

2797.68

30

2341.84

2465.09

2588.34

35

1936.58

2038.51

2140.43

40

1611.20

1696.00

1780.80

45

1348.27

1419.23

1490.19

50

1134.48

1194.19

1253.89

55

959.62

1010.13

1060.63

Inlet Air Temp Sensor Resistance (room temp) 

FUEL SYSTEM (EFI) 3-41

Inlet Air Temperature Sensor

Inlet Air Temperature Sensor Circuit

1. ECU                                             2 . Inlet Temperature Sensor

3-42 FUEL SYSTEM (EFI)

Water Temperature Sensor

Water Temperature Sensor Removal/Installa-

tion



Drain the coolant (see Coolant Change in the Peri-

   odic Maintenance chapter).



 Disconnect the sensor connector [A], and unscrew

   the water temperature sensor [B].

   Torque - Water Temperature Sensor: 12 N m (1.
   2 kgf

m, 106 in lb)



 Apply grease to new O-ring on the water tempera-

   ture sensor.



 Fill the engine with coolant and bleed the air from

   the cooling system (see Coolant Change in the Pe-
   riodic Maintenance chapter).

Water Temperature Sensor Output Voltage

Inspection

NOTE

 Be sure the battery is fully charged.



 Remove the ECU (see ECU Removal). Do not dis-

   connect the connectors.



 Connect a hand tester [A] to the ECU connector [B]

   with the needle adapter set.



 Measure  the  sensor  output  voltage  with  the

   engine stopped and the connector joined.



 Turn the ignition switch ON.

   Water Temperature  Sensor Output Voltage

   Hand tester(+) Gr/W lead(ECU terminal 29)
   Hand tester(-) L/G lead(ECU terminal 27)
   Standard: 2.5~3.5 V (20°C)

FUEL SYSTEM (EFI) 3-43

Coolant Temperature Sensor

    NOTE

Coolant temperature sensor output voltage varies with the coolant temperature change.



 Turn the ignition switch off.



If the output voltage is within the standard, check the ECU for its ground, and power supply (see ECU Power

   Supply Inspection).



If the output voltage is out of the standard, check the wiring. And if the output voltage is 4.8 V, the ECU is nor-

   mal.



If the wiring is good, check the water temperature sensor resistance.

   Remove  the  needle  adapter  set,  and  apply  silicone
   sealant to the seals of the connector for waterproofing.

Water Temperature Sensor Circuit

1. ECU                       2 . Coolant Temperature Sensor                    3. Meter Unit

Coolant Temperature Sensor Resistance Inspection



 Remove coolant temperature sensor (refer to 

Coolant Temperature Sensor Removal/Installation

).



 Refer to 

Coolant Temperature Sensor Inspection

.

3-44 FUEL SYSTEM (EFI)

Crankshaft Position Sensor



 Refer to the Crankshaft Sensor Removal/Installation in the Electrical System chapter.

Crankshaft  Position Sensor Removal/Installation

Crankshaft Position Sensor Inspection



 The crankshaft sensor has no power source, and when the engine stops, the crankshaft sensor generates no

   signals.



 Crank the engine and measure the peak voltage of the crankshaft position sensor (see Crankshaft Sensor

   Inspection in the Electrical System) in order to check the sensor.



 Check the wiring for continuity, using the following diagram.

Crankshaf Position Sensor Circuit

   1. ECU            2. Crankshaft Position Sensor

FUEL SYSTEM (EFI) 3-45

Speed Sensor

Speed Sensor Removal/Installation



 Refer to the Speed Sensor Removal/Installation in

   the Electrical System chapter.

Speed Sensor Inspection



 Refer to the Speed Sensor Inspection in the Elec-

   trical System chapter.

Speed Sensor Input Voltage Inspection

NOTE

Be sure the battery is fully charged.



 Turn the ignition switch OFF.



 Disconnect the speed sensor connector and con-

   nect the harness adapter [A] between the harness
   connector and speed sensor connector.



 Connect a hand tester to the harness adapter leads.



 Measure  the  sensor  input  voltage  with  the  en-

   gine stopped, and with the connector joined.



 Turn the ignition switch ON.

   

Speed Sensor Input Voltage

   

Connection  to Adapter

  

 Meter (+) 

 B/Br (sensor) lead [C]

   Meter (-) 

 G/B (sensor) lead [D]

   Standard: About 9~13 V DC at Ignition Switch

   ON



If the reading is out of the range, check the wiring

   (see wiring diagram in this section), and meter (see
   Electronic Combination Meter Unit Inspection in the
   Electrical System chapter).



If the reading is good, check the output voltage.



 Turn the ignition switch OFF.

   Speed Sensor Output Voltage



 Before this inspection,  inspect the input voltage

   (see Speed Sensor Input Voltage Inspection).

NOTE

Be sure the battery is fully charged.



 Turn the ignition switch OFF.



 Disconnect the speed sensor connector and con

   nect the harness adapter [A] between the harness
   connector and speed sensor connector.



 Connect a hand tester to the harness adapter leads.

3-46 FUEL SYSTEM (EFI)



 Measure  the  sensor  output  voltage  with  the

   engine stopped, and with the connector joined.



 Turn the ignition switch ON.

 

  Speed Sensor Output Voltage at Sensor

 

  Connections  to Adapter

   Meter (+)

 P (sensor) lead [C]

   Meter (-)

G/B(sensor) lead [D]

   Standard: About 0.05~1.0 V DC

Speed Sensor

      1. Speed Sensor                              2. Meter Unit

      Speed Sensor Circuit

FUEL SYSTEM (EFI) 3-47

Roll-over Sensor

Roll-over Sensor Removal



 Removal:

   Disconnect connector [B] and roll-over sensor [A].



 Installation:

   Roll-over sensor should be installed as illustrated.

Roll-over Sensor Output Voltage Inspection (when

tilted)



 Connect a hand tester [A] to the connector [B] of

   the roll-over sensor [C] with the needle adapter set
   [D].



 Measure  the  sensor  output  voltage  with  the  en-

   gine stopped, and with the connector joined.



 Turn the ignition switch ON.

   Roll-over Sensor Output Voltage

   

Meter(+)

Gr/B lead [E]

   Meter (-)

L/G lead [F]

Never drop the sensor, especially on a hard

surface. Such a shock to the part can damage it.

N

O

I

T

U

A

C

Incorrect installation of the vehicle-down sensor

could cause sudden loss of engine power.

The rider could lose balance during certain riding

situ- ations like leaning over in a turn with the

potential for an accident resulting in injury or

death. Ensure that the down sensor is held in

place by the sensor brackets.

G

N

I

N

R

A

W

NOTE

Be sure the battery is fully charged.

!

3-48 FUEL SYSTEM (EFI)



 Turn the ignition switch on and measure roll-over

   sensor power source voltage.

   Roll-over Sensor

   Roll-over Sensor Output Voltage(when tilted):

  

 Standard:

   4.75~5.25V (connector disconnected)

   3.5~4.0V (connector joined)



 Turn the ignition switch OFF.



If the reading of input voltage is less than the

   standard, check the ECU for its ground, power sup-
   ply and wiring shorted.



If the wiring is normal, check roll-over sensor

   resistance.



 Remove the sensor [D]  (see Roll-over Sensor

   Removal).



 Connect a hand tester [A] to the connector [B]

   with needle adapter set [D].

   Roll-over Sensor Output Voltage

   Meter(+)

Gr/B lead [E]

   Meter(-)

L/G lead [F]

  Roll-over Sensor Output Voltage Inspection

  (when tilted)



 Hold the sensor vertically.



 Turn the ignition switch ON, and measure the out-

   put voltage with the connector joined.



 Tilt the sensor  40~50

o

 or more [C] right or left, then

   and measure the output voltage.

NOTE

If you need to test again, turn the ignition switch

  OFF, and then ON.



 Turn the ignition switch OFF.



 Remove  the  needle  adapter  set,  and  apply

   silicone sealant to the seals of the connector for
   waterproofing.



If the output voltage is normal, the wiring is suspect.

   Check the wiring.



If the wiring is good, check the ECU for its ground

  and power supply (see ECU Power Supply
    Inspection).



If the output voltage is out of the specified, replace

   the roll-over sensor.