CFMoto motorcycle CF650NK. Service Manual - part 14

FUEL SYSTEM (EFI) 3-17

EFI Servicing Precautions

O

 Lead Color Codes:

   B: Black           L: Blue         Gr: Grey
   B: Brown          G: Green      Lg: Light green
   Sb: Sky blue    O: Orange     R: Red
   P: Purple         W: White      Y: Yellow

O

 There are two ways to inspect the EFI system.  One

  is voltage Check Method and the other is Resistance
  Check Method.

  (Voltage Check Method)

O

 This method is conducted by measuring the input

   voltage [B] to a sensor [A] first, and then the output
   voltage [C] from the sensor.

O

 

Sometimes this method can detect a fault of the

   ECU.
o Refer to each sensor inspection section for detail in
   this chapter.
o Use a fully charged battery and a digital meter [D]
   which can be read two decimal places voltage or
   resistance.

   (Resistance Check Method)

o This method is simple. No need for a fully charged
   battery and the needle adapter. Just do the follow
   ing especially when a sensor [A] is suspect.
o Turn the ignition switch OFF and disconnect the
   connectors.
o Inspect the sensor resistance, using a digital meter
  (see each sensor inspection).
o Inspect the wiring and connectors [B] for continuity,
   using the hand tester [C] (analog tester) rather than
   a digital meter.

  

 Special Tool -  Hand Tester

   If the sensor, the wiring and connections are good,
   inspect the ECU for its ground and power supply
   (see ECU Power Supply Inspection). If the ground
   and power supply are good, the ECU is suspect.
   Replace the ECU.

3-18 FUEL SYSTEM (EFI)

    EFI Servicing Precautions

    EFI Diagnosis Flow Chart

Problem occurs.

Confirm problems.

Gather information from rider.

The ignition switch is turned on, and the state of FI indicator
light (LED) is seen.

Unlit

Lit

Conduct non-self-diagnosis
inspection

Conduct self-diagnosis
inspection

Conduct general fuel system
inspection

End

Inquiries to Rider



 Each rider reacts to problems in different ways, so it is important to confirm what kind of

   symptoms the rider has encountered.



 Try to find out exactly what problem occurred under exactly what conditions by asking the

   rider; knowing this information may help you reproduce the problem.



 The following sample diagnosis sheet will help prevent you from overlooking any areas, and

   will help you decide if it is an EFI system problem, or a general engine problem.

FUEL SYSTEM (EFI) 3-19

Sample Diagnosis Sheet

Rider name:

Registration No. (license plate No.):

Year of initial registration: Model:

Engine No.:

Frame No.:

Date problem occurred:

Mileage:

Environment when problem occurred.

Weather

□

fi

 ne, 

□

cloudy,

□

rain, 

□

snow, 

□

always, 

□

other:

Temperature

□

hot, 

□

warm, 

□

cold, 

□

very cold, 

□

always

Problem frequency

□

chronic, 

□

often, 

□

once

Road

□

street, 

□

highway, 

□

mountain road (

□

uphill, 

□

downhill), 

□

bumpy, 

□

pebble

Altitude

□

normal, 

□

high (about 1 000 m or more)

Motorcycle conditions when problem occurred.

FI indicator light (LED)

□

light up immediately after ignition switch ON, and goes off after 1 ~2 

seconds (normal)

□

lights blinks immediately after ignition switch ON, and stays on (EFI 

problem)

□

lights up immediately after ignition switch ON, but goes off after about 

10 seconds (EFI problem)

□

unlights (light (LED), ECU or its wiring fault)

□

sometimes lights up (probably wiring fault)

Starting dif

fi

 culty

□

starter motor not rotating

□

starter motor rotating but engine doesn’t turn over

□

starter motor and engine don’t turn over

□

no fuel 

fl

 ow (

□

no fuel in tank, 

□

no fuel pump sound)

□

engine flooded (do not crank engine with throttle opened, which 

promotes engine 

fl

 ooding)

□

no spark

□

other

Engine stops

□

right after starting

□

when opening throttle grip

□

when closing throttle grip

□

when moving off

□

when stopping the motorcycle

□

when cruising

□

other

Poor running at low speed

□

very low idle speed, 

□

very high idle speed, 

□

rough idle speed

□

battery voltage is low (charge the battery)

□

spark plug loose (tighten it)

□

spark plug dirty, broken, or gap maladjusted (remedy it)

□

back

fi

 ring

□

after

fi

 ring

□

hesitation when acceleration

□

engine oil viscosity too high

□

brake dragging

□

engine overheating

□

clutch slipping

3-20 FUEL SYSTEM (EFI)

Sample Diagnosis Sheet

ƑRWKHU

3RRUUXQQLQJRUQRSRZHUDW
KLJKVSHHG

ƑVSDUNSOXJORRVHWLJKWHQLW
ƑVSDUNSOXJGLUW\EURNHQRUJDSPDODGMXVWHGUHPHG\LW
ƑVSDUNSOXJLQFRUUHFWUHSODFHLW
ƑNQRFNLQJIXHOSRRUTXDOLW\RULQFRUUHFWĺXVHKLJKRFWDQHJDVROLQH
ƑEUDNHGUDJJLQJ
ƑFOXWFKVOLSSLQJ
ƑHQJLQHRYHUKHDWLQJ
ƑHQJLQHRLOOHYHOWRRKLJK
ƑHQJLQHRLOYLVFRVLW\WRRKLJK
ƑRWKHU

FUEL SYSTEM (EFI) 3-21

NOTE

○

 This is not an exhaustive list, giving every possible cause for each problem listed.  It is meant

   simply as a rough guide to assist the troubleshooting for some of the more common dif

fi

 culties.

○

 The ECU may be involved in the EFI electrical and ignition system troubles. If these parts and

   circuits are 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.

   Engine Doesn’t Start, Starting Diffi culty

Symptoms or possible Causes

Actions (chapter)

Starter motor not rotating:

Ignition and engine stop switches not ON

Turn both switches ON.

Starter lockout switch or neutral switch trouble

Inspect (see chapter 16).

Starter motor trouble

Inspect (see chapter 16).

Battery voltage low

Inspect and charge (see chapter 16).

Starter relays not contacting or operating

Inspect the starter relay (see chapter 16).

Starter button not contacting

Inspect and replace (see chapter 16).

Starter system wiring open or shorted

Inspect the wiring (see chapter 16).

Ignition switch trouble

Inspect and replace (see chapter 16).

Engine stop switch trouble

Inspect and repair or replace (see chapter 16).

Main 30A or ignition fuse blown

Inspect and replace (see chapter 16).

Starter motor rotating but engine doesn’t turn over:

Starter clutch trouble

Inspect (see chapter 16).

Starter idle gear trouble

Inspect (see chapter 16).

Engine won’t turn over:
Valve seizure

Inspect and replace (see chapter 5).

Cylinder, piston seizure

Inspect and replace (see chapter 5).

Camshaft seizure

Inspect and replace (see chapter 5).

Connecting rod small end seizure

Inspect and replace (see chapter 5).

Connecting rod big end seizure

Inspect and replace (see chapter 5).

Crankshaft seizure

Inspect and replace (see chapter 5).

Transmission gear or bearing seizure

Inspect and replace (see chapter 5).

Balancer bearing seizure

Inspect and replace (see chapter 5).

No fuel fl ow:

No or little fuel in tank

Supply fuel (see Owner’s Manual).

Fuel pump not rotating

Inspect (see chapter 3).

Fuel injector trouble

Inspect and replace (see chapter 3).

Fuel tank air vent obstructed

Inspect and repair (see chapter 3).

Fuel 

fi

 lter or pump screen clogged

Inspect and replace fuel pump (see chapter 3).

Fuel pressure regulator clogged

Inspect and replace fuel pump (see chapter 3).

Fuel line clogged

Inspect and repair (see chapter 3).

Engine fl ooded:

Spark plug dirty, broken or gap maladjusted

Replace (see chapter 2).

Starting technique faulty

When 

fl

 ooded, don’t crank engine with throttle 

fully opened.

No spark or spark weak:

Ignition and engine stop switches not ON

Turn both switches ON .

3-22 FUEL SYSTEM (EFI)

Symptoms or possible Causes

Actions (chapter)

Clutch lever not pulled in and gear not in neutral 
whether sidestand up or not

Pull the lever in and shift the gear in neutral.

Though clutch lever pulled in, sidestand up and 
gear not in neutral

Sidestand down and clutch lever pulled in whether 
gear in neutral or not

Vehicle-down-sensor coming off

Reinstall (see chapter 3).

Vehicle-down-sensor trouble

Inspect (see chapter 3).

ECU ground or power supply trouble

Inspect (see chapter 3).

Battery voltage low

Inspect and charge (see chapter 16).

Spark plug dirty, broken or gap maladjusted

Replace (see chapter 2).

Stick coil trouble

Inspect stick coil (see chapter 16).

Stick coil shorted or not in good contact

Reinstall or inspect stick coil (see chapter 16).

Spark plug incorrect

Replace it with the correct plug (see chapter 16).

IC igniter in ECU trouble

Inspect (see chapter 16).

Neutral, starter lockout or sidestand switch trouble

Inspect each switch (see chapter 16).

Crankshaft sensor trouble

Inspect (see chapter 16).

Stick coil trouble

Inspect (see chapter 16).

Ignition switch shorted

Inspect and replace (see chapter 16).

Engine stop switch shorted

Inspect and repair or replace (see chapter 2).

Starter system wiring shorted or open

Inspect and repair or replace (see chapter 16).

Main 30A or ignition fuse blown

Inspect and replace (see chapter 16).

Fuel/air mixture incorrect:

Air cleaner clogged, poorly sealed or missing

Clean or reinstall (see chapter 3).

Leak from oil 

fi

 ller cap, crankcase breather hose or 

air cleaner drain hose

Inspect and repair or replace (see chapter 3).

Water or foreign matter in fuel

Change fuel. Inspect and clean fuel system (see 
chapter 3).

Fuel pressure regulator trouble

Inspect fuel pressure and replace fuel pump (see 
chapter 3).

Main throttle sensor trouble

Inspect (see chapter 3).

Fuel pressure may be low

Inspect (see chapter 3).

Fuel pump trouble

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3)

Water temperature sensor trouble

Inspect (see chapter 3).

Crankshaft sensor trouble

Inspect (see chapter 3).

Compression low:

Spark plug loose

Reinstall (see chapter 16).

Cylinder head not suf

fi

 ciently tightened down

Tighten (see chapter 5).

Cylinder, piston worn

Inspect and replace (see chapter 5).

Piston ring bad (worn, weak, broken or sticking)

Inspect and replace (see chapter 5).

Piston ring/groove clearance excessive

Inspect and replace (see chapter 5).

Cylinder head gasket damaged

Replace (see chapter 5).

Cylinder head warped

Inspect and replace (see chapter 5).

No valve clearance

Adjust (see chapter 2).

Valve guide worn

Inspect and replace (see chapter 5).

Valve spring broken or weak

Inspect and replace (see chapter 5).

Valve not seating properly (valve bent, worn or 
carbon accumulating on seating surface)

Inspect and repair or replace (see chapter 5).

FUEL SYSTEM (EFI) 3-23

Symptoms or Possible Causes

Actions (chapter)

Spark weak:

Battery voltage low

Inspect and charge (see chapter 16).

Spark plug dirty, broken or gap maladjusted

Replace (see chapter 2).

Stick coil trouble

Inspect the stick coil (see chapter 16).

Stick coil shorted or not in good contact

Reinstall or inspect stick coil (see chapter 16).

Spark plug incorrect

Replace it with the correct plug (see chapter 16).

IC igniter in ECU trouble

Inspect (see chapter 16).

Crankshaft position sensor trouble

Inspect (see chapter 16).

Stick coil trouble

Inspect (see chapter 16).

Fuel/air mixture incorrect:

Little fuel in tank

Supply fuel (see Owner’s Manual).

Air cleaner clogged, poorly sealed, or missing

Clean element or inspect sealing (see chapter
2, 3).

Air cleaner duct loose

Reinstall (see chapter 3).

Air cleaner O-ring damaged

Replace (see chapter 3).

Fuel tank air vent obstructed

Inspect and repair (see chapter 3).

Throttle body assy loose

Reinstall (see chapter 3).

Throttle body assy O-ring damage

Replace (see chapter 3).

Fuel 

fi

 lter or pump screen clogged

Inspect and replace fuel pump (see chapter 3).

Fuel pressure regulator clogged

Inspect fuel pressure and replace fuel pump (see 
chapter 3).

Fuel line clogged

Inspect and repair (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Thermostat trouble

Inspect and replace (see chapter 4).

Unstable (rough) idling:

Fuel injector trouble

Inspect (see chapter 3).

Main throttle sensor trouble

Inspect (see chapter 3).

Crankshaft position sensor trouble

Inspect (see chapter 3).

Throttle valves not synchronizing

Inspect (see chapter 2).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Coolant temperature sensor trouble

Inspect (see chapter 3).

Fuel pressure too low or too high

Inspect (see chapter 3).

Battery voltage low

Inspect and charge (see chapter 16).

Incorrect idle speed:

Coolant temperature sensor trouble

Inspect (see chapter 3)

Main throttle sensor trouble

Inspect (see chapter 3).

3-24 FUEL SYSTEM (EFI)

Symptoms or Possible Causes

Actions (chapter)

Engine stalls easily:

Fuel pump trouble

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Main throttle sensor trouble

Inspect (see chapter 3).

Fuel pressure too low or too high

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Coolant temperature sensor trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Fuel line clogged

Inspect and repair (see chapter 3).

Fuel pressure too low or too high

Inspect (see chapter 3).

Fuel pressure regulator trouble

Inspect fuel pressure and replace fuel pump (see 
chapter 3).

Crankshaft sensor trouble

Inspect (see chapter 16).

Stick coil trouble

Inspect (see chapter 16).

Compression Low:

Spark plug loose

Reinstall (see chapter 16).

Cylinder head not suf

fi

 ciently tightened down

Tighten (see chapter 5).

No valve clearance

Adjust (see chapter 2).

Cylinder, piston worn

Inspect and replace (see chapter 5).

Piston ring bad (worn, weak, broken or sticking )

Inspect and replace (see chapter 5).

Piston ring/groove clearance excessive

Inspect and replace (see chapter 5).

Cylinder head gasket damaged

Replace (see chapter 5).

Cylinder head warped

Inspect and replace (see chapter 5).

Valve guide worn or stem seal damaged

Inspect and replace (see chapter 5).

Valve spring broken or weak

Inspect and replace (see chapter 5).

Valve not seating properly (valve bent, worn or 
carbon accumulating on seating surface)

Inspect and repair or replace (see chapter 5).

Camshaft cam worn

Inspect and replace (see chapter 5).

Hesitation:

Too low fuel pressure

Inspect (see chapter 3).

Clogged fuel line

Inspect and repair (see chapter 3).

Cracked or obstructed inlet air pressure sensor 
hose

Inspect and repair or replace (see chapter 3).

Fuel pump trouble

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Main throttle sensor trouble

Inspect (see chapter 3).

Subthrottle sensor trouble

Inspect (see chapter 3).

Subthrottle valve actuator trouble

Inspect (see chapter 3).

Coolant temperature sensor trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Loose injector connectors

Remedy (see chapter 3).

Crankshaft position sensor trouble

Inspect and repair or replace (see chapter 16).

Stick coil trouble

Inspect and repair or replace (see chapter 16).

Loose terminal of battery (–) cable or engine ground 
lead

Inspect and repair (see chapter 16).

Delay of ignition timing

Inspect crankshaft sensor and IC igniter in ECU (see 
chapter 16).

FUEL SYSTEM (EFI) 3-25

Symptoms or Possible Causes

Actions (chapter)

Loose terminal of battery (–) cable or engine ground 
lead

Inspect and repair (see chapter 16).

Delay of ignition timing

Inspect crankshaft sensor and IC igniter in ECU (see 
chapter 16).

Poor acceleration:

Too low fuel pressure

Inspect (see chapter 3).

Water or foreign matter in fuel

Change fuel. Inspect and clean fuel system (see 
chapter 3).

Clogged fuel 

fi

 lter or pump screen

Inspect and replace fuel pump (see chapter 3).

Fuel pump trouble

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Coolant temperature sensor trouble

Inspect (see chapter 3).

Subthrottle sensor trouble

Inspect (see chapter 3).

Subthrottle valve actuator trouble

Inspect (see chapter 3).

Stick coil trouble

Inspect and replace (see chapter 16).

Engine oil level to high

Repair (see chapter 7).

Spark plug dirty, broken or gap maladjusted

Replace (see chapter 2).

Stumble:

Too low fuel pressure

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Main throttle sensor malfunction

Inspect (see chapter 3).

Subthrottle sensor trouble

Inspect (see chapter 3).

Subthrottle valve actuator trouble

Inspect (see chapter 3).

Coolant temperature sensor trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Surge:

Unstable fuel pressure

Fuel pressure regulator trouble (Inspect and replace 
fuel pump) or kinked fuel line (Inspect and repair 
fuel line) (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Water temperature sensor trouble

Inspect (see chapter 3).

Back

fi

 ring when deceleration:

Spark plug dirty, broken or gap maladjusted

Replace (see chapter 2).

Too low fuel pressure

Inspect (see chapter 3).

Fuel pump trouble

Inspect (see chapter 3).

Main throttle sensor trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Water temperature sensor trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Air switching valve broken

Inspect and replace (see chapter 5).

Air suction valve trouble

Inspect and replace (see chapter 5).

After fi re:

Crankshaft position sensor trouble

Inspect (see chapter 16).

Spark plug burned or gap maladjusted

Replace (see chapter 2).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Water temperature sensor trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

3-26 FUEL SYSTEM (EFI)

Symptoms or Possible Causes

Actions (chapter)

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Coolant temperature sensor trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Fuel injector trouble

Inspect (see chapter 3).

Run-on (dieseling):

Ignition switch trouble

Inspect and replace (see chapter 16).

Engine stop switch trouble

Inspect and repair or replace (see chapter 2).

Fuel injector trouble

Inspect (see chapter 3).

Loose terminal of battery (–) cable or ECU

ground lead

Inspect and repair (see chapter 16).

Carbon accumulating on valve seating surface

Repair (see chapter 5).

Engine overheating

(see Overheating of Troubleshooting Guide, see 

chapter 17)

Other:

Engine oil viscosity too high

Change (see chapter 2).

Drive train trouble

Inspect drive chain (see chapter 2) and sprocket

(see chapter 11).

Brake dragging

Inspect caliper fluid seal damage or clogging of 

master cylinder relief and supply ports (see chapter 

12).

Clutch slipping

Inspect friction plates for wear (see chapter 6).

Engine overheating

(see Overheating of Troubleshooting Guide, see 

chapter 17)

Air switching valve trouble

Inspect and replace (see chapter 5).

Air suction valve trouble

Inspect and replace (see chapter 5).

Intermittent any EFI fault and its recovery

Check that EFI connectors are clean and tight, and 

examine wires for signs of burning or fraying (see 

chapter 3).

Poor Running or No Power at High Speed

Symptoms or Possible Causes

Actions (chapter)

Firing incorrect:

Spark plug dirty, broken or maladjusted

Replace (see chapter 2).

Stick coil trouble

Inspect stick coil (see chapter 16).

Stick coil shorted or not in good contact

Reinstall or inspect stick coil (see chapter 16).

Spark plug incorrect

Replace it with the correct plug (see chapter 16).

IC igniter in ECU trouble

Inspect (see chapter 16).

Crankshaft sensor trouble

Inspect (see chapter 16).

Stick coil trouble

Inspect (see chapter 16).

Fuel/air mixture incorrect:

Air cleaner clogged, poorly sealed, or missing

Clean element or inspect sealing (see chapter 3).

Air cleaner duct loose

Reinstall (see chapter 3).

Air cleaner O-ring damaged

Replace (see chapter 3).

Water or foreign matter in fuel

Change fuel. Inspect and clean fuel system (see 

chapter 3).

Throttle body assy loose

Reinstall (see chapter 3).

FUEL SYSTEM (EFI) 3-27

Symptoms or Possible Causes

Actions (chapter)

Throttle body assy O-ring damaged

Replace (see chapter 3).

Fuel tank air vent obstructed

Inspect and repair (see chapter 3).

Fuel line clogged

Inspect and repair (see chapter 3).

Fuel pump operates intermittently and often EFI

fuse blows.

Pump bearings may wear. Replace the pump

(see chapter 3).

Fuel pump trouble

Inspect (see chapter 3).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Main throttle sensor trouble

Inspect (see chapter 3).

Inlet air pressure sensor trouble

Inspect (see chapter 3).

Cracked or obstructed inlet air pressure sensor 

hose

Inspect and repair or replace (see chapter 3).

Injector clogged

Visually inspect and replace (see chapter 3).

Compression low:

Spark plug loose

Reinstall (see chapter 16).

Cylinder head not sufficiently tightened down

Tighten (see chapter 5).

No valve clearance

Adjust (see chapter 2).

Cylinder, piston worn

Inspect and replace (see chapter 5).

Piston ring bad (worn, weak, broken or sticking) Inspect and replace (see chapter 5).
Piston ring/groove clearance excessive

Inspect and replace (see chapter 5).

Cylinder head gasket damaged

Replace (see chapter 5) .

Cylinder head warped

Inspect and replace (see chapter 5).

Valve spring broken or weak

Inspect and replace (see chapter 5).

Valve not seating properly (valve bent , worn or 

carbon accumulating on the seating surface)

Inspect and repair or replace (see chapter 5).

Knocking:

Carbon built up in combustion chamber

Repair (see chapter 5).

Fuel poor quality or incorrect (Use the gasoline 

recommended in the Owner’s Manual)

Change fuel (see chapter 3).

Spark plug incorrect

Replace it with the correct plug (see chapter 16).

Stick coil trouble

Inspect (see chapter 16).

IC igniter in ECU trouble

Inspect (see chapter 16).

Inlet air temperature sensor trouble

Inspect (see chapter 3).

Miscellaneous:

Throttle valves won’t fully open

Inspect throttle cable and lever linkage (see chapter 3).

Brake dragging

Inspect caliper fluid seal damage or clogging of master 

cylinder relief and supply ports (see chapter 12).

Clutch slipping

Inspect friction plates for wear (see chapter 6).

Engine overheating - Water temperature sensor, 

crankshaft sensor or speed sensor trouble

(see Overheating of Troubleshooting Guide in chapter 

17).

Engine oil level too high

Repair (see chapter 7).

Engine oil viscosity too high

Change (see chapter 2).

3-28 FUEL SYSTEM (EFI)

Symptoms or Possible Causes

Actions (chapter)

Drive train trouble

Inspect drive chain (see chapter 2) and sprockets
(see chapter 11).

Camshaft cam worn

Inspect and replace (see chapter 5).

Air switching valve trouble

Inspect and replace (see chapter 5).

Air suction valve trouble

Inspect and replace (see chapter 5).

Catalytic converters melt down due to muffler 
overheating

Replace muf

fl

 er (see chapter 5).

Exhaust Smokes Excessively:
(White smokes)
Piston oil ring worn

Inspect and replace (see chapter 5).

Cylinder worn

Inspect and replace (see chapter 5).

Valve oil seal damaged

Replace (see chapter 5).

Valve guide worn

Replace the guide (see chapter 5).

Engine oil level too high

Repair (see chapter 7).

(Black smoke)
Air cleaner clogged

Clean (see chapter 3).

Too high fuel pressure

Clean (see chapter 3).

Injector stuck open

Clean (see chapter 3).

Coolant temperature sensor trouble

Inspect and replace (see chapter 3).

Inlet air temperature sensor trouble

Inspect and replace (see chapter 3).

(Brown smoke)
Air cleaner duct loose

Reinstall (see chapter 3). 

Air cleaner O-ring damaged 

Replace (see chapter 3).

Too low fuel pressure

Inspect fuel line and fuel pump (see chapter 3).

Water temperature sensor trouble 

 

Inspect and replace (see chapter 3).

Inlet air temperature sensor trouble

Inspect and replace (see chapter 3).

FUEL SYSTEM (EFI) 3-29

Self-diagnosis Outline

O

 ECU constantly monitor sensors, actuators and

   circuits, FI indicator light and battery voltage, etc,
   even ECU itself and inspect the sensor output signal,
   actuator drive signal and internal signal ( such as

close loop control, coolant temperature, idel

   speed control and battery voltage control, etc.) for
   reliablity. If any process or signal is suspect, ECU
   records the trouble code in the RAM memory.
   Faulty information is recorded in the form of trouble
   code, and in the sequence of which trouble comes
   first. Trouble code is divided into 2 parts: present
   trouble code and past trouble code.
   When servicing, using PDA and FI indicator, the de-
   fective parts can be promptly foud to improve the
   service efficiency and quality.

Self-diagnosis Procedures

Self-diagnosis Procedures

O

 When a problem occurs with the EFI system and

   ignition system, the FI indicator light (LED) [A] goes
   on.

NOTE

O

 

Use a fully charged battery when conducting self-

  diagnosis. Otherwise, the light (LED) blinks very

   slowly or doesn’t blink.

FI Indicator Light Conditions

1) Turn on the ignition switch and the engine does

    not work. No trouble code appears:



 FI indicator light keeps on for 5 seconds and then

   turns off.

2)Turn on the ignition switch and the engine

   works. Only one trouble code:



 FI indicator light keeps on for 10 seconds and then

   starts to blink the trouble code.



 FI indicator light turns off 10 seconds after blinking

   the trouble code, then blinks the trouble code in
   turn.



 FI indicator works in turn as above until the engine

   runs (if possible) or ignition switch is turned off.

3-30 FUEL SYSTEM (EFI)

Self-diagnosis Procedures



Keep on full throttle and turn on the ignition switch.



FI indicator light turns off (keep on full throttle).



FI indicator keeps on for 5 seconds after full throttle is kept on 10 seconds. During the 5 seconds, turn off the

    ignition switch.



Above is the procedure of reset if 

the maintenance is overtime.



When the maintenace is overtime again, repeat the procedure above.

5)Turn on the ignition switch and the engine does not work. Trouble code is displayed after

    maintenance interval:



 FI indicator light keeps on for 10 seconds and turns off, then blink the trouble codes in turn. When the first

   trouble code is blinked, FI indicator keeps on for 10 seconds and turns off, then blinks the second trouble
   code. FI indicator light works in this manner unitil all the trouble codes are displayed.



 Afterwards, FI indicator light starts to blink the first trouble code until the last one.



 FI indicator light runs in cycle until the engine starts to work or the ignition switch is turned off.



Overtime maintenance trouble only be displayed after no other trouble codes are left to be displayed.



 Restore the EFI system and turn on the ignition switch. The engine does not work and the same condition

   appears again as the 4th point as above(no trouble code appears after maintenance interval).

How to Read Trouble Codes
How to Read Service Codes



Trouble codes are shown by a series of long and short blinks of the FI indicator light (LED) as shown

    below.



Read 10th digit and unit digit as the FI indicator light (LED) blinks.

  



  When there are a number of problems, all the trouble codes can be stored and the display will

      begin starting from the lowest number trouble code in the numerical order. Then after completing
      all codes, the display is repeated until the self-diagnosis indicator terminal is open.
  



  If there is no problem, no code and unlight.

  



  For example, if two problems occurred in the order of 21, 12, the trouble codes are displayed from

      the lowest number in the order listed.
      (12

21)  (12

21) 

(repeated)

3) Turn on the ignition switch, the engine does not work and a number of trouble codes appear:



FI indicator light keeps on for 10 seconds and turns off, then starts to blink the trouble codes. When the

    first trouble code is blinked, FI indicat light keeps on for 10 seconds and then off. Then FI indicator light
    starts to blink the second trouble code. FI indiicator blinks in turn as above. When the last touble code
    is blinked, FI indicator light keeps on for 10 seconds and then off.



Then FI indicator light blink all the trouble codes in the sequence as above again.



The circle stops until the engine works or ignition switch is turned off.

4) Turn on the ignition switch and the engine does not work. No trouble code appears after mainte-

    nance interval:

FUEL SYSTEM (EFI) 3-31



Even if ignition switch is turned off, the battery or the ECU is disconnected or the problem is solved, all
trouble codes remain in ECU.



As for present trouble codes, if the trouble still exsits, present trouble codes can not be cleared; when the

    trouble is solved, service codes are cleared automatically but turned into past trouble codes. Past trouble
    codes can be deleted with PDA.

How to Erase Trouble Codes

How to Erase Trouble Codes

3-32 FUEL SYSTEM (EFI)

    Self-Diagnosis
    Trouble Code Table

Short blink [S.B.] =unit digit of trouble coode      Long blink [L.B.] =10th

digit of trouble code  S.C. = Short to battery positive terminal  S.C.G = Short circuit to ground

O.C. = Open Circuit

s

m

e

l

b

o

r

P

e

d

o

C

r

o

r

r

E

s

e

m

i

T

k

n

il

B

w

o

L

_

)

r

o

s

n

e

S

n

o

it

i

s

o

P

e

lt

t

o

r

h

T

(

S

P

T

-

r

o

r

r

E

1

).

B

.

S

(

1

h

g

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H

_

)

r

o

s

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e

S

n

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i

s

o

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e

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t

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r

h

T

(

S

P

T

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r

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E

2

)

B

.

S

(

2

H

T

-

r

o

r

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E

2

w

o

l

_

)

r

o

s

n

e

S

.

p

m

e

T

r

e

t

a

W

(

O

3

).

B

.

S

(

3

H

T

-

r

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E

2

h

g

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H

_

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r

o

s

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e

S

.

p

m

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T

r

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t

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W

(

O

4

).

B

.

S

(

4

w

o

L

_

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r

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s

n

e

S

.

p

m

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T

ri

A

(

R

I

A

T

-

r

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r

r

E

5

).

B

.

S

(

5

h

g

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H

_

)

r

o

s

n

e

S

.

p

m

e

T

ri

A

(

R

I

A

T

-

r

o

r

r

E

6

).

B

.

S

(

6

w

o

L

_

)

r

o

s

n

e

S

e

r

u

s

s

e

r

P

ri

A

(

R

I

A

P

-

r

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r

r

E

7

).

B

.

S

(

7

h

g

i

H

_

)

r

o

s

n

e

S

e

r

u

s

s

e

r

P

ri

A

(

R

I

A

P

-

r

o

r

r

E

8

).

B

.

S

(

8

w

o

L

_

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e

g

a

tl

o

V

y

r

e

tt

a

B

(

V

B

-

r

o

r

r

E

9

).

B

.

S

(

9

C

S

_

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r

o

t

c

e

j

n

i

r

e

d

n

ill

y

c

1

(

1

J

N

I-

r

o

r

r

E

1

1

).

B

.

S

(

1

+

)

B

.

L

(

1

G

C

S

_

)

r

o

t

c

e

j

n

i

r

e

d

n

ill

y

c

1

(

1

J

N

I-

r

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r

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E

2

1

).

B

.

S

(

2

+

)

B

.

L

(

1

C

O

_

)

r

o

t

c

e

j

n

i

r

e

d

n

ill

y

c

1

(

1

J

N

I-

r

o

r

r

E

3

1

).

B

.

S

(

3

+

)

B

.

L

(

1

C

S

_

)

r

o

t

c

e

j

n

i

r

e

d

n

ill

y

c

2

(

2

J

N

I-

r

o

r

r

E

4

1

).

B

.

S

(

4

+

)

B

.

L

(

1

G

C

S

_

)

r

o

t

c

e

j

n

i

r

e

d

n

ill

y

c

2

(

2

J

N

I-

r

o

r

r

E

5

1

).

B

.

S

(

5

+

)

B

.

L

(

1

C

O

_

)

r

o

t

c

e

j

n

i

r

e

d

n

ill

y

c

2

(

2

J

N

I-

r

o

r

r

E

6

1

).

B

.

S

(

6

+

)

B

.

L

(

1

C

S

_

)

y

a

l

e

R

n

a

F

(

R

N

A

F

-

r

o

r

r

E

3

2

).

B

.

S

(

3

+

)

B

.

L

(

2

C

O

_

)

y

a

l

e

R

n

a

F

(

R

N

A

F

-

r

o

r

r

E

5

2

).

B

.

S

(

5

+

)

B

.

L

(

2

C

S

_

)

y

a

l

e

R

n

i

a

M

(

R

N

I

A

M

_

r

o

r

r

E

6

2

).

B

.

S

(

6

+

)

B

.

L

(

2

C

O

_

)

y

a

l

e

R

n

i

a

M

(

R

N

I

A

M

_

r

o

r

r

E

8

2

).

B

.

S

(

8

+

)

B

.

L

(

2

C

S

_

)

y

a

l

e

R

r

e

tr

a

t

S

y

r

a

il

i

x

u

A

(

R

T

S

N

E

_

r

o

r

r

E

9

2

).

B

.

S

(

9

+

)

B

.

L

(

2

C

S

_

)t

h

g

il

r

o

t

a

c

i

d

n

i

r

o

r

r

E

(

P

M

A

L

D

_

r

o

r

r

E

5

3

).

B

.

S

(

5

+

)

B

.

L

(

3

G

C

S

_

)t

h

g

il

r

o

t

a

c

i

d

n

i

r

o

r

r

E

(

P

M

A

L

D

_

r

o

r

r

E

6

3

).

B

.

S

(

6

+

)

B

.

L

(

3

C

O

_

)t

h

g

il

r

o

t

a

c

i

d

n

i

r

o

r

r

E

(

P

M

A

L

D

_

r

o

r

r

E

7

3

).

B

.

S

(

7

+

)

B

.

L

(

3

C

O

_

)

r

o

s

n

e

S

n

e

g

y

x

O

r

e

d

n

il

y

c

1

(

1

A

D

B

M

A

L

_

r

o

r

r

E

7

4

).

B

.

S

(

7

+

)

B

.

L

(

4

C

O

_

)

r

o

s

n

e

S

n

e

g

y

x

O

r

e

d

n

il

y

c

2

(

2

A

D

B

M

A

L

_

r

o

r

r

E

8

4

).

B

.

S

(

8

+

)

B

.

L

(

4

0

)

r

o

s

n

e

S

r

e

v

o

-l

l

o

R

(

W

S

Y

T

E

F

A

S

_

r

o

r

r

E

9

4

).

B

.

S

(

9

+

)

B

.

L

(

4

1

)

r

o

s

n

e

S

r

e

v

o

-l

l

o

R

(

W

S

Y

T

E

F

A

S

_

r

o

r

r

E

0

5

)

B

.

L

(

5

C

O

_

)

p

u

k

c

i

P

(

K

P

_

r

o

r

r

E

3

5

).

B

.

S

(

3

+

)

B

.

L

(

5

)

p

u

k

c

i

P

(

K

P

_

r

o

r

r

E

4

5

).

B

.

S

(

4

+

)

B

.

L

(

5

T

N

E

R

R

U

C

_

)l

i

o

c

n

o

it

i

n

g

i

r

e

d

n

il

y

c

1

(

1

N

G

I

_

r

o

r

r

E

5

5

).

B

.

S

(

5

+

)

B

.

L

(

5

T

N

E

R

R

U

C

_

li

o

c

n

o

it

i

n

g

i

r

e

d

n

il

y

c

1

(

1

N

G

I

_

r

o

r

r

E

6

5

).

B

.

S

(

6

+

)

B

.

L

(

5