If the radiator fan relay is normal, check the wiring for continuity, using the wiring diagram in this section.
Special Tool - Hand Tester: 57001-1394
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).
Radiator Fan Circuit

1. ECU
2. Fan Motor
3. Ignition Switch
4. Joint Connector F
5. Fuse Box 1
6. Ignition Fuse 15 A
7. Relay Box
8. Fan Relay
9. Frame Ground 3
10. Fuse Box 2
11. Fan Fuse 15 A
12. Starter Relay
13. Main Fuse 30 A
14. Battery
15. Engine Ground
Radiator Fan Relay Removal/InstallationPiston Ring Thickness Inspection
Measure the piston ring thickness.
Use the micrometer to measure at several points around
the ring.
Piston Ring Thickness
Standard:
Top [A] 0.77 0.79 mm (0.0303
0.0311 in.)
Second [B] 0.78 0.79 mm
(0.0307 0.0311 in.)
Service Limit:
Top 0.70 mm (0.0276 in.)
Second 0.71 mm (0.0280 ...
Air Switching Valve
Air Switching Valve Operation Test
Refer to the Air Suction System Damage Inspection in the
Periodic Maintenance chapter.
Air Switching Valve Unit Test
Remove the air switching valve (see Air Switching Valve
Removal in the Engine Top End chapter).
Set the hand tester [A] to the × 1 ...
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 ...