For Stick Coil #4
Digital Meter (+) → BK/G lead (terminal 43)
Digital Meter (–) → Battery (–) Terminal

the input voltage to each primary winding of the
• Measure
stick coils with the engine stopped and with the connec-

•
•

tors joined.
Turn the engine stop switch to run position.
Turn the ignition switch on.
Input Voltage
Standard: Battery Voltage

FUEL SYSTEM (DFI) 3-95
Stick Coils #1, #2, #3, #4 (Service Code 51, 52, 53, 54) (DTC P0351, P0352, P0353,
P0354)
the ignition switch off.
• Turn
If the input voltage is out of the standard, check the wiring
for continuity (see Stick Coil Circuit).
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).
If the input voltage is within the standard, check the ECU
for its ground and power supply (see ECU Power Supply
Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

Stick Coil Circuit

1. Ignition Switch
2. Fuse Box (1)
3. Ignition Fuse 15 A
4. Engine Stop Switch
5. Stick Coil #1
6. Stick Coil #2
7. Stick Coil #3
8. Stick Coil #4
9. ECU
10. Frame Ground (9)
11. Engine Ground
12. Battery 12 V 8 Ah
13. Starter Relay
14. Main Fuse 30 A

3-96 FUEL SYSTEM (DFI)
Radiator Fan Relay (Service Code 56) (DTC P0480)
Radiator Fan Relay Removal/Installation

○The radiator fan relay is built in the relay box [A].

to the Relay Box Removal in the Electrical System
• Refer
chapter.

Radiator Fan Relay Inspection

to the Relay Circuit Inspection in the Electrical Sys• Refer
tem chapter.
If the radiator fan relay is normal, check the wiring for
continuity (see Radiator Fan Relay Circuit).
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

Radiator Fan Relay Circuit

1. Ignition Switch
2. Fan Motor
3. Fuse Box (1)
4. Ignition Fuse 15 A
5. Fan Fuse 15 A
6. Water Temperature Sensor
7. ECU
8. Engine Ground

9. Battery 12 V 8 Ah
10. Starter Relay
11. Main Fuse 30 A
12. Relay Box
13. Radiator Fan Relay
14. Frame Ground (8)
15. Frame Ground (7)

FUEL SYSTEM (DFI) 3-97
Subthrottle Valve Actuator (Service Code 62) (DTC P2100)
Subthrottle Valve Actuator Removal
NOTICE
Do not remove the subthrottle valve actuator [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 subthrottle valve
actuator can damage it.

Subthrottle Valve Actuator Inspection
NOTE

○Be sure the battery is fully charged.
the air cleaner housing (see Air Cleaner Housing
• Remove
Removal).
the ignition switch on.
• Turn
Check
to see that all the subthrottle valves [A] open and
• close smoothly.
the ignition switch off.
• Turn
If the subthrottle valves do not operate, check the subthrottle valve actuator resistance (see Subthrottle Valve
Actuator Resistance Inspection).

Subthrottle Valve Actuator Resistance Inspection

the ignition switch off.
• Turn
the air cleaner housing (see Air Cleaner Housing
• Remove
Removal).
• Disconnect the subthrottle valve actuator connector [A].

a digital meter to the subthrottle valve actuator
• Connect
connector [A].
• Measure the subthrottle valve actuator resistance.
Subthrottle Valve Actuator Resistance
Connections: Y/BK lead [1] ←→ P/BL lead [2]
G lead [3] ←→ BK/O lead [4]
Standard:

About 5.2  7.8 Ω

If the reading is out of the standard, replace the throttle
body assy (see Throttle Body Assy Removal/Installation).
If the reading is within the standard, check the input voltage (see Subthrottle Valve Actuator Input Voltage Inspection).

3-98 FUEL SYSTEM (DFI)
Subthrottle Valve Actuator (Service Code 62) (DTC P2100)
Subthrottle Valve Actuator Input Voltage
Inspection
NOTE

○Be sure the battery is fully charged.
the ignition switch off.
• Turn
Remove
• Removal).the air cleaner housing (see Air Cleaner Housing
the subthrottle valve actuator connector and
• Disconnect
connect the measuring adapter [A] between these connectors as shown.
Main Harness [B]
Subthrottle Valve Actuator [C]
Special Tool - Measuring Adapter: 57001-1700

the peak voltage adapter [D] and a digital meter
• Connect
[E] to the measuring adapter leads.
Special Tool - Peak Voltage Adapter: 57001-1415
Type: KEK-54-9-B
Subthrottle Valve Actuator Input Voltage
Connections to Adapter:
(I) Digital Meter (+) → R (actuator BK/O) lead
Digital Meter (–) → BK (actuator G) lead
(II) Digital Meter (+) → W (actuator P/BL) lead
Digital Meter (–) → Y (actuator Y/BK) lead

the actuator input voltage with
• Measure
stopped and with the connector joined.
• Turn the ignition switch on.

the engine

Input Voltage
Standard: About DC 8.5  10.5 V and then 0 V or
About DC 8.5  10.5 V

the ignition switch off.
• Turn
If the reading is in specification, but the actuator does not
operate, replace the throttle body assy (see Throttle Body
Assy Removal/Installation).
If the reading is out of the specification, remove the ECU
and check the wiring for continuity between main harness
connectors.
○Disconnect the ECU and actuator connectors.
Wiring Continuity Inspection
ECU Connector [A] ←→
Subthrottle Valve Actuator Connector [B]
ECU Terminal 1 [C] ←→ Actuator Terminal [D]
ECU Terminal 12 [E] ←→ Actuator Terminal [F]
ECU Terminal 23 [G] ←→ Actuator Terminal [H]
ECU terminal 24 [I] ←→ Actuator Terminal [J]

If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

FUEL SYSTEM (DFI) 3-99
Subthrottle Valve Actuator (Service Code 62) (DTC P2100)
Subthrottle Valve Actuator Circuit

1. Subthrottle Valve Actuator
2. ECU

3-100 FUEL SYSTEM (DFI)
Air Switching Valve (Service Code 64) (DTC P0410)
Air Switching Valve Removal/Installation

to the Air Switching Valve Removal/Installation in
• Refer
the Engine Top End chapter.

Air Switching Valve Inspection

to the Air Switching Valve Unit Test in the Electrical
• Refer
System chapter.
If the air switching valve is normal, check the wiring for
continuity (see Air Switching Valve Circuit).
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

Air Switching Valve Circuit

1. Ignition Switch
2. Air Switching Valve
3. Fuse Box (1)
4. Ignition Fuse 15 A
5. ECU
6. Joint Connector B
7. Engine Ground
8. Battery 12 V 8 Ah

9. Starter Relay
10. Main Fuse 30 A
11. ECU Fuse 15 A
12. Relay Box
13. ECU Main Relay
14. Frame Ground (7)
15. Frame Ground (6)

FUEL SYSTEM (DFI) 3-101
Oxygen Sensor Heater (Service Code 67) (DTC P0030)
Oxygen Sensor Heater Removal/Installation
The oxygen sensor heater is built in the oxygen sensor.
So, the heater itself can not be removed. Remove the oxygen sensor (see Oxygen Sensor Removal in the Electrical
System chapter).

Oxygen Sensor Heater Resistance Inspection
the ignition switch off.
• Turn
Remove:
• Fuel Tank (see Fuel Tank Removal)
• Disconnect the oxygen sensor lead connector [A].

a digital meter [A] to the oxygen sensor lead con• Connect
nector [B].
• Measure the oxygen sensor heater resistance.
Oxygen Sensor Heater Resistance
Connections: BK lead [C] ←→ BK lead [D]
Standard: 11.7  15.5 Ω @20°C (68°F)

If the reading is out of the standard, replace the sensor.
If the reading is within the standard, check the power
source voltage (see Oxygen Sensor Heater Power
Source Voltage Inspection).

3-102 FUEL SYSTEM (DFI)
Oxygen Sensor Heater (Service Code 67) (DTC P0030)
Oxygen Sensor Heater Power Source Voltage
Inspection
NOTE

○Be sure the battery is fully charged.
the ignition switch off.
• Turn
Remove:
• Fuel Tank (see Fuel Tank Removal)
the oxygen sensor lead connector and con• Disconnect
nect the measuring adapter [A] between these connectors.
Main Harness [B]
Oxygen Sensor [C]
Special Tool - Measuring Adapter: 57001-1700

• Connect a digital meter [D] to the measuring adapter lead.
Oxygen Sensor Power Source Voltage
Connections to Adapter:
Digital Meter (+) → R (main harness BR/W) lead
Digital Meter (–) → Frame Ground Terminal

the power source voltage with
• Measure
stopped and with the connector joined.
• Turn the ignition switch on.

the engine

Power Source Voltage
Standard: Battery Voltage

the ignition switch off.
• Turn
If the reading is in specification, but the problem still exists, replace the ECU (see ECU Removal/Installation).
If the reading is out of the standard, check the following.
ECU Fuse 15 A (see Fuse Inspection in the Electrical
System chapter)
Power Source Wiring (see Oxygen Sensor Circuit)
If the fuse and wiring are good, remove the ECU and
check the wiring for continuity between main harness connectors.
○Disconnect the ECU and sensor connectors.
Wiring Continuity Inspection
ECU Connector [A] ←→
Oxygen Sensor Connector [B]
ECU Terminal 64 [C] ←→ Sensor Terminal [D]

If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

FUEL SYSTEM (DFI) 3-103
Oxygen Sensor Heater (Service Code 67) (DTC P0030)
Oxygen Sensor Circuit

1. Ignition Switch
2. Fuse Box (1)
3. Ignition Fuse 15 A
4. Oxygen Sensor
5. ECU
6. Joint Connector B
7. Engine Ground
8. Battery 12 V 8 Ah
9. Starter Relay
10. Main Fuse 30 A
11. ECU Fuse 15 A
12. Relay Box
13. ECU Main Relay
14. Frame Ground (6)

3-104 FUEL SYSTEM (DFI)
Fuel Supply System (Service Code 94) (DTC P0170)
Fuel Supply System Inspection
NOTE

○If the motorcycle has any other service code, first inspect the other service code.
the General fuel system (throttle body assy, air
• Inspect
cleaner, fuel tank etc.).
If the General fuel system is good, check the ECU for
its ground and power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

FUEL SYSTEM (DFI) 3-105
Purge Valve (Service Code 3A, Equipped Models) (DTC P0443)
Purge Valve Removal/Installation

• Remove:
Fuel Tank (see Fuel Tank Removal)
Disconnect
purge valve connector [A].
• Remove thethepurge
valve mounting nut [B].
• Remove the purge valve
• Slide the clamps [D]. [C] from the bracket.
• Disconnect the hoses [E].
• Installation is the reverse of removal.
• Run the hoses correctly (see Cable, Wire, and Hose Rout• ing section in the Appendix chapter).
• Tighten:
Torque - Purge Valve Mounting Nut: 6.9 N·m (0.70 kgf·m, 61
in·lb)

Purge Valve Inspection

the purge valve (see Purge Valve Removal/In• Remove
stallation).
a digital meter [A] to the purge valve terminals
• Connect
as shown.
Purge Valve Resistance
Standard: 30  34 Ω @20°C (68°F)

If the resistance reading is out of the specified value, replace it with a new one.
the 12 V battery [A] to the purge valve terminals
• Connect
as shown.

the air to the intake air duct [A], and make sure that
• Blow
the air flows from the outlet air duct [B].

3-106 FUEL SYSTEM (DFI)
Purge Valve (Service Code 3A, Equipped Models) (DTC P0443)
the 12 V battery.
• Disconnect
Blow
the
air
to the intake air duct [A] again, and make sure
• that the air does
not flow from the outlet air duct [B].
If the purge valve dose not operate as described, replace
it with a new one.
If the purge valve is good, check the wiring for continuity
(see Purge Valve Circuit).
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).

Purge Valve Circuit

1. Ignition Switch
2. Fuse Box (1)
3. Ignition Fuse 15 A
4. Purge Valve
5. ECU
6. Joint Connector B
7. Engine Ground
8. Battery 12 V 8 Ah
9. Starter Relay
10. Main Fuse 30 A
11. ECU Fuse 15 A
12. Relay Box
13. ECU Main Relay
14. Frame Ground (7)
15. Frame Ground (6)

FUEL SYSTEM (DFI) 3-107
Warning Indicator Light (LED)
Yellow Engine Warning/Red Warning Indicator
Light (LED) Inspection
Yellow Engine Warning Indicator Light (LED) [A]
Red Warning Indicator Light (LED) [B]
○In this model, the above mentioned warning indicator
lights (LED) go on or blink by the data sent from the ECU.
Refer to the Meter Unit Inspection in the Electrical System
chapter.

•

Warning Indicator Light (LED) Circuit

1. ECU
2. Frame Ground (10)
3. Meter Unit
4. Yellow Engine Warning Indicator Light (LED)
5. Red Warning Indicator Light (LED)

3-108 FUEL SYSTEM (DFI)
ECU
ECU Identification

○Most countries have their own regulations, so each ECU
has different characteristic. So, do not confuse ECU with
each other and use only the ECU for your model. Otherwise, the motorcycle cannot clear the regulation.
ECU Identification (ZR900A Model)
Part Number [A]
21175-1226
21175-1238
21175-1280

Specification
CAL, without Immobilizer
US, with Immobilizer
CA, without Immobilizer
MY, with Immobilizer

ECU Identification (ZR900B Model)
Part Number [A]
21175-1212

Specification
SEA-B1, with Immobilizer
WVTAFULL, with Immobilizer

21175-1224

ID, with Immobilizer

21175-1225

CH, with Immobilizer

21175-1239

US, without Immobilizer
CA, without Immobilizer

21175-1240

CAL, without Immobilizer

21175-1241

TH, with Immobilizer

21175-1245

AU, with Immobilizer
MY, with Immobilizer

ECU Removal
NOTICE
Never drop the ECU especially on a hard surface.
Such a shock to the ECU can damage it.

○Refer

NOTE

to the Immobilizer System Parts Replacement
in the Electrical System chapter for the models with
guards.

• Remove:
Fuel Tank (see Fuel Tank Removal)
WVTA (FULL) model, remove the screws [A] and ECU
• For
guards [B].

FUEL SYSTEM (DFI) 3-109
ECU

• Disconnect:
Relay Box Connectors [A]
ECU Connectors [B]

up the ECU [A] with rubber protector [B] to clear the
• Lift
projections [C].

• Remove the ECU [A] from the rubber protector [B].

ECU Installation

is the reverse of removal.
• Installation
Insert
the
slit
hole of the rubber protector to the pro• jections [A] ofand
the air cleaner housing.
• Install the removed parts (see appropriate chapters).

ECU Power Supply Inspection

inspect the ECU connectors.
• Visually
If the connector is clogged with mud or dust, blow it off

•
•

with compressed air.
Remove the ECU (see ECU Removal).
Visually inspect the terminals [A] of the ECU and main
harness connectors.
If the terminals of the main harness connectors are damaged, replace the main harness.
If the terminals of the ECU connectors are damaged, replace the ECU.

3-110 FUEL SYSTEM (DFI)
ECU
the ignition switch off.
• Turn
Disconnect
the ECU connectors.
• Gray Connector
[A]
Set
a
tester
[B]
and
check the following wiring for conti• nuity.
ECU Grounding Inspection
Connections:
(I) ECU Terminal 38, 39
or 65

←→ Battery (–) Terminal