NOTE
Be sure the battery is fully charged.
Main Harness [B] Vehicle-down Sensor [C]
Special Tool - Measuring Adapter: 57001-1700

Vehicle-down Sensor Input Voltage Connections to Adapter: Digital Meter (+) → R (sensor BL) lead Digital Meter (–) → BK (sensor BR/BK) lead

Input Voltage
Standard: DC 4.75
5.25 V
If the reading is within the standard, check the output voltage (see Vehicle-down Sensor Output Voltage Inspection).
If the reading is out of the standard, remove the ECU and check the wiring for continuity between main harness connectors.
Special Tool - Hand Tester: 57001-1394
Disconnect the ECU and sensor connectors.
Wiring Continuity Inspection ECU Connector [A] ←→ Vehicle-down Sensor Connector [B] BL lead (ECU terminal 9) [C] BR/BK lead (ECU terminal 13) [D]

If the wiring is good, check the ECU for its ground and power supply (see ECU Power Supply Inspection in the Fuel System (DFI) chapter).
If the ground and power supply are good, replace the ECU (see ECU Removal/Installation in the Fuel System (DFI) chapter).
Vehicle-down Sensor Installation
Vehicle-down Sensor Output Voltage InspectionCoupling Bearing Installation
Replace the bearing with a new one.
Press in the bearing [A] until it is bottomed.
Special Tool - Bearing Driver Set [B]: 57001-1129
Pack the bearing with high-temperature grease.
Replace the circlip with a new one.
Special Tool - Inside Circlip Pliers: 57001-143
Replace the grease se ...
DFI Parts Location
Main Throttle Sensor [A]
Subthrottle Sensor [B]
Idle Speed Control Valve Actuator [C]
Subthrottle Valve Actuator [D]
Intake Air Pressure Sensor #2 [E]
Stick Coils #1, #2, #3, #4 [F]
Air Switching Valve [G]
Intake Air Pressure Sensor #1 [H]
Water Temperature Sensor [A]
Primary Fuel Injec ...
Special Tools
Inside Circlip Pliers:
57001-143
Oil Seal & Bearing Remover:
57001-1058
Bearing Driver Set:
57001-1129
Jack:
57001-1238
Bearing Remover Head, 15 ×
17:
57001-1267
Fork Oil Level Gauge:
57001-1290
Bearing Remover Shaft, 13:
57001-1377
Fork Oil Seal Driver, 43:
57001-15 ...