ECU YAMAHA YZF-R1SC 2004 Workshop Manual

8-2
9Radiator fan motor relay
10Turn signal relay
11Rectifier / regulator
12Throttle position sensor
13Sub-throttle position sensor
1Coolant temperature sensor
2Intake air temperature sensor
3Intake air pressure sensor
4Fuel pump
5ECU
6Lean angle cut-off switch
7Starting circuit cut-off relay
8Headlight relay (dimmer)
ELECTRICAL COMPONENTSELEC
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8-13
IGNITION SYSTEMELEC
12. Starting circuit cut-off relay (diode)

Disconnect the starting circuit cut-off relay
coupler from the wire harness.

Connect the pocket tester (Ω
1) to the
starting circuit cut-off relay coupler as
shown.

Check the starting circuit cut-off relay for
continuity.
Positive tester probe

blue / yellow
Negative tester probe

sky blue
1
2
EAS00753
Positive tester probe

blue / yellow
Negative tester probe

blue / black Continuity
1
3
Positive tester probe

sky blue
Negative tester probe

blue / yellow
2
1
Positive tester probe

blue / black
Negative tester probe

blue / yellow No
continuity
3
1
YESNO
Replace the starting
circuit cut-off relay. When you switch the positive and negative
tester probes, the readings in the above chart
will be reversed.

Are the tester readings correct?
NOTE:
13. Lean angle cut-off switch

Check the lean angle cut-off switch.
Refer to “FUEL INJECTION SYSTEM” in
chapter 7.

Is the lean angle cut-off switch OK?
YESNO
Replace the lean
angle cut-off switch.
EAS00754
14. Wiring

Check the entire ignition system’s wiring.
Refer to “CIRCUIT DIAGRAM”.

Is the ignition system’s wiring properly con-
nected and without defects?
YESNO
Properly connect or
repair the ignition
system’s wiring.
Replace the ECU.
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8-49
FUEL PUMP SYSTEMELEC
1Battery
2Fuse (main)
3Main switch
4Fuse (ignition)
5Engine stop switch
6ECU
7Fuse (fuel injection)
8Starting circuit cut-off relay (fuel injection
system relay)
9Fuel pump
EAS00815
FUEL PUMP SYSTEM
The ECU includes the control unit for the
fuel pump.
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8-51
FUEL PUMP SYSTEMELEC
YESNO 5. Starting circuit cut-off relay (fuel injection
system relay)

Disconnect the starting circuit cut-off relay
coupler from the wire harness.

Connect the pocket tester (Ω
1) and bat-
tery (12 V) to the starting circuit cut-off relay
coupler as shown.
Replace the starting
circuit cut-off relay.
Positive battery lead
red / black
Negative battery lead
blue / yellow 1
2
Positive tester probe
red
Negative tester probe
red / blue3
4

Does the starting circuit cut-off relay have
continuity between red and red / blue?
YESNO 6. Fuel pump resistance

Disconnect the fuel pump coupler from the
wire harness.

Connect the pocket tester (Ω
1) to the fuel
pump coupler as shown.
Properly connect or
repair the fuel sys-
tem’s wiring.
1
2
Positive tester probe
red / blue
Negative tester probe
black
EAS00817
YESNO Fuel pump resistance
0.2  3.0 Ω at 20C (68F)

Is the fuel pump OK?
Replace the fuel
pump.

Measure the fuel pump resistance.
7. Wiring

Check the entire fuel pump system’s wiring.
Refer to “CIRCUIT DIAGRAM”.

Is the fuel system’s wiring properly con-
nected and without defects?
EAS00818
Replace the ECU.
EAS00759
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9-1
STARTING FAILURES
TRBL
SHTG
NOTE:
FUEL SYSTEM
Fuel tank
Empty fuel tank

Clogged fuel filter

Clogged fuel strainer

Clogged fuel tank drain hose

Deteriorated or contaminated fuel
Fuel pump
Faulty fuel pump

Faulty fuel pump relay
Throttle body (-ies)

Deteriorated or contaminated fuel

Sucked-in air
Ignition coil(s)
Cracked or broken ignition coil body

Broken or shorted primary or secondary
coils
Ignition system
Faulty ECU

Faulty crankshaft position sensor
EAS00844
TROUBLESHOOTING
The following guide for troubleshooting does not cover all the possible \
causes of trouble. It should be
helpful, however, as a guide to basic troubleshooting. Refer to the relative procedure i\
n this manual for
checks, adjustments, and replacement of parts.
STARTING FAILURES
ENGINE
Cylinder(s) and cylinder head(s)

Loose spark plug

Loose cylinder head or cylinder

Damaged cylinder head gasket

Damaged cylinder gasket

Worn or damaged cylinder

Incorrect valve clearance

Improperly sealed valve

Incorrect valve-to-valve-seat contact

Incorrect valve timing

Faulty valve spring

Seized valve
Piston(s) and piston ring(s)
Improperly installed piston ring

Damaged, worn or fatigued piston ring

Seized piston ring

Seized or damaged piston
Air filter
Improperly installed air filter

Clogged air filter element
Crankcase and crankshaft
Improperly assembled crankcase

Seized crankshaft
ELECTRICAL SYSTEMS
Battery
Discharged battery

Faulty battery
Fuse(s)
Blown, damaged or incorrect fuse

Improperly installed fuse
Spark plug(s)

Incorrect spark plug gap

Incorrect spark plug heat range

Fouled spark plug

Worn or damaged electrode

Worn or damaged insulator
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9-2
9
Starting system
Faulty starter motor

Faulty starter relay

Faulty starting circuit cut-off relay

Faulty starter clutch
STARTING FAILURES / INCORRECT ENGINE IDLING SPEED /
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCETRBL
SHTG
ELECTRICAL SYSTEMS
Battery

Discharged battery

Faulty battery
Spark plug(s)
Incorrect spark plug gap

Incorrect spark plug heat range

Fouled spark plug

Worn or damaged electrode

Worn or damaged insulator
Ignition coil(s)

Broken or shorted primary or secondary
coils

Cracked or broken ignition coil
Ignition system
Faulty ECU

Faulty crankshaft position sensor
Switches and wiring

Faulty main switch

Faulty engine stop switch

Broken or shorted wiring

Faulty neutral switch

Faulty start switch

Faulty sidestand switch

Faulty clutch switch

Improperly grounded circuit

Loose connections
EAS00846
INCORRECT ENGINE IDLING SPEED
ENGINE
Cylinder(s) and cylinder head(s)

Incorrect valve clearance

Damaged valve train components
Air filter
Clogged air filter element
FUEL SYSTEM
Throttle body (-ies)
Damaged or loose throttle body joint

Improperly synchronized throttle bodies

Improperly adjusted engine idling speed (idle
adjusting screw)

Improper throttle cable free play

Flooded throttle body

Faulty air induction system
EAS00848
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE
Refer to “STARTING FAILURES”.
ENGINE
Air filter

Clogged air filter element
FUEL SYSTEM
Fuel pump
Faulty fuel pump
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