If the connector is clogged with mud or dust, blow it off with compressed air.
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.

Gray Connector [A]

Special Tool - Hand Tester: 57001-1394
ECU Grounding Inspection
Connections:
(I) BK/Y leads (ECU terminal 40, 73 or 74) ←→ Battery (–) Terminal
(II) Engine Ground ←→ Battery (–) Terminal
Criteria: Both: 0 Ω
If no continuity, check the connectors, the engine ground lead, or main harness, and repair or replace them if necessary.
If the wiring is good, check the power source voltage of the ECU.

NOTE
Be sure the battery is fully charged.
Special Tool - Needle Adapter Set: 57001-1457
ECU Power Supply Inspection Connections:
(I) Digital Meter (+) → Terminal 41 (W/BK)
Digital Meter (–) → Battery (–) terminal
(II) Digital Meter (+) → Terminal 53 (BR/W)
Digital Meter (–) → Battery (–) terminal
(III) Digital Meter (+) → Terminal 54 (W/BK)
Digital Meter (–) → Battery (–) terminal
Ignition Switch OFF:
Terminal 41 (W/BK): Battery Voltage
Terminal 53 (BR/W): 0 V
Terminal 54 (W/BK): Battery Voltage
Ignition Switch ON:
All: Battery Voltage
If the reading is out of the specification, check the following.
Main Fuse 30 A (see Fuse Inspection in the Electrical System chapter)
ECU Fuse 15 A (see Fuse Inspection in the Electrical System chapter)
ECU Main Relay (see Relay Circuit Inspection in the Electrical System chapter)
Power Source Wiring (see wiring diagram in this section)
If the fuse, wiring and relay are good, replace the ECU (see ECU Removal/Installation).
ECU Removal
ECU Power Source CircuitSpecial Tools
Bearing Puller:
57001-135
Head Pipe Outer Race Press Shaft:
57001-1075
Steering Stem Nut Wrench:
57001-1100
Bearing Driver Set:
57001-1129
Steering Stem Bearing Driver, 42.5:
57001-1344
Steering Stem Bearing Driver Adapter,
41.5:
57001-1345
Head Pipe Outer Race Driver, 55:
57001- ...
Coolant Level Inspection
NOTE
Check the level when the engine is cold (room or ambient
temperature).
Check the coolant level in the reserve tank [A] with the
motorcycle held perpendicular (Do not use the sidestand).
If the coolant level is lower than the “L” level line [B], remove
the upper fairing assembly (s ...
Subthrottle Valve Actuator Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Disconnect the subthrottle valve actuator connector and
connect the measuring adapter [A] between these connectors
as shown in the figure.
Main Harness [B]
Subthrottle Valve Actuator [C]
Special Tool ...