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/InstallationChain Slack Adjustment
Remove the cotter pin, and loosen
the axle nut.
Loosen the left and right chain adjuster
locknuts.
A. Axle Nut
B. Cotter Pin
C. Adjuster
D. Locknut
If the chain is too loose, turn out the
left and right chain adjusters evenly.
If the chain is too tight, turn in the left
...
Check 2-3: Intake Air Temperature Inspection
Disconnect the intake air temperature sensor connector
[A] (see Intake Air Temperature Sensor Removal in the
Self-Diagnosis System chapter).
Connect the variable rheostat [B] to the R/BK lead [C] and
BR/BK lead [D] terminals.
Turn the ignition switch to ON.
Read the temperatur ...
Bolts, Nuts and Fasteners Tightness Inspection
Check the tightness of the bolts and nuts listed here. Also,
check to see that each cotter pin is in place and in good
condition.
NOTE
For the engine fasteners, check the tightness of them
when the engine is cold (at room temperature).
If there are loose fasteners, retighten them to ...