If the reading is within the standard, but the problem still exists, replace the ECU (see ECU Removal/Installation in the Fuel System (DFI) chapter).
Water Temperature Sensor Circuit

1. ECU
2. Water Temperature Sensor
Water Temperature Sensor Output Voltage InspectionKIBS Hydraulic Unit Inspection
Remove the KIBS hydraulic unit (see KIBS Hydraulic Unit
Removal).
Visually inspect the connector terminals [A].
Replace the KIBS hydraulic unit or main harness if either
of the terminals are cracked, bent, or otherwise damaged.
If the KIBS hydraulic unit connector is clogged with mud
or ...
Spark Plug Condition Inspection
Remove the spark plugs (see Spark Plug Replacement in
the Periodic Maintenance chapter).
Visually inspect the spark plugs.
If the spark plug center electrode [A] and/or side electrode
[B] are corroded or damaged, or if the insulator [C]
is cracked, replace the plug.
If the spark plug is ...
Air Suction Valve Installation
Install the air suction valve so that opening [A] of the reed
faces downward.
Apply a non-permanent locking agent to the threads of
the air suction valve cover bolts [A], and tighten them.
Torque - Air Suction Valve Cover Bolts: 9.8 N·m (1.0 kgf·m,
87 in·lb)
...