Disconnect the main throttle sensor connector and connect the setting adapter [A] between these connectors.

Special Tool - Throttle Sensor Setting Adapter: 57001 -1538
Main Throttle Sensor Output Voltage Connections to Adapter: Digital Meter (+) → R (sensor V/W) lead
Digital Meter (–) → BK (sensor BR/BK) lead
Install the following parts temporarily.
Throttle Body Assy (see Throttle Body Assy Installation in the Fuel System (DFI) chapter) Air Cleaner Housing (see Air Cleaner Housing Installation in the Fuel System (DFI) chapter) Fuel Tank (see Fuel Tank Installation in the Fuel System (DFI) chapter)
Throttle Sensor Setting Adapter [A]
Idle Speed Standard: 1 100 ±50 r/min (rpm)

Output Voltage
Standard: DC 0.64
0.68 V at idle
throttle opening
DC 3.89
4.09 V at full throttle
opening (for
reference)
NOTE
Example: In the case of a input voltage of 4.75 V.
0.64 × 4.75 ÷ 5.00 = 0.61 V
0.68 × 4.75 ÷ 5.00 = 0.65 V
Thus, the valid range is 0.61
0.65 V
If the reading is out of the standard, replace the throttle body assy.
If the reading is within the standard, remove the ECU and check the wiring for continuity between harness connectors.
Special Tool - Hand Tester: 57001-1394
Disconnect the ECU and sensor connectors.

Wiring Continuity Inspection ECU Connector [A] ←→ Main Throttle Sensor Connector [B] V/W lead (ECU terminal 25) [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).
Main Throttle Sensor Circuit

1. ECU
2. Subthrottle Sensor
3. Main Throttle Sensor
Main Throttle Sensor Resistance InspectionECU Removal
NOTICE
Never drop the ECU especially on a hard surface.
Such a shock to the ECU can damage it.
Remove the upper air cleaner housing (see Air Cleaner
Element Replacement in the Periodic Maintenance chapter).
Lift up the ECU [A] with rubber protector [B] to disconnect
the connectors [C]. ...
Premuffler Chamber Installation
Replace the premuffler chamber gasket [A] with a new
one.
Install the premuffler chamber gasket to the premuffler
chamber [B] until it is bottomed so that the chamfer side
faces exhaust pipe [C].
Install the exhaust pipe clamp [D] as shown in the figure.
Insert the projection [E] into ...
Hub Bearing Inspection
Since the hub bearings are made to extremely close tolerances,
the clearance can not normally be measured.
NOTE
Do not remove any bearings for inspection. If any bearings
are removed, they will need to be replaced with
new ones.
Turn each bearing in the hub back and forth [A] while
checki ...