If this service code appears, check that the following parts are correctly.
Crankshaft Sensor Gear Position Switch Starter Lockout Switch Main Throttle Sensor Rear Wheel Rotation Sensor
If these parts are normal, check the ESD ECU for its ground and power supply (see ESD ECU Power Supply Inspection).
ESD ECU Removal
ESD ECU Installation
Refer to the ESD (Electronic Steering Damper) ECU Installation in the Steering chapter.
ESD ECU Power Supply Inspection

If the connector is clogged with mud or dust, blow it off with compressed air.
If the terminals of the main harness connector are damaged, replace the main harness.
If the terminals of the ESD ECU connectors are damaged, replace the ESD ECU.
Special Tool - Hand Tester: 57001-1394

ESD ECU Grounding Inspection Connections: (I) BK/Y lead (ESD ECU terminal 9) ←→ Battery (–) Terminal (II) Engine Ground ←→ Battery (–) Terminal Criteria: Both: 0 Ω
If no continuity, check the connector, 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 ESD ECU.
NOTE
Be sure the battery is fully charged.

Special Tool - Needle Adapter Set: 57001-1457
ESD ECU Power Supply Inspection Connections:
(I) Digital Meter (+) → Terminal 18 (BR/BK) Digital Meter (–) → Battery (–) terminal
Ignition Switch OFF: 0 V
Ignition Switch ON: 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) Electronic Steering Damper Fuse 10 A (see Fuse Inspection in the Electrical System chapter) Power Source Wiring (see wiring diagram in this section)
If the fuse and wiring are good, replace the ESD ECU (see ESD (Electronic Steering Damper) ECU Removal/Installation in the Steering chapter).
ESD ECU Power Source Circuit

1. Ignition Switch
2. ESD ECU
3. Engine Ground
4. Battery
5. Starter Relay
6. Main Fuse 30 A
7. Frame Ground 3
8. Fuse Box 1
9. ESD Fuse 10 A
ESD Actuator Input Voltage InspectionSubthrottle Valve Actuator Resistance Inspection
Turn the ignition switch to OFF.
Disconnect the subthrottle valve actuator connector [A].
Connect a digital meter to the subthrottle valve actuator
connector [A].
Measure the subthrottle valve actuator resistance.
Subthrottle Valve Actuator Resistance
Connections: Y/BK lead [1 ...
Front Wheel Rotation Sensor Signal Abnormal (Service Code b 42)
Measure the air gap between the front wheel rotation sensor
and sensor rotor.
Thickness Gauge [A]
Air Gap
Standard: 0.4 1.6 mm (0.02
0.06 in.)
If the measurement is not the standard, check each part
for deformation and looseness and correct accordingly.
If the measurement is t ...
Brake Pad Wear Inspection
Remove the brake pads (see Front/Rear Brake Pad Removal
in the Brakes chapter).
Check the lining thickness [A] of the pads in each caliper.
If the lining thickness of either pad is less than the service
limit [B], replace both pads in the caliper as a set.
Front Brake Pad [C]
Rea ...