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 InspectionCrankshaft Sensor Peak Voltage Inspection
Refer to the Crankshaft Sensor Peak Voltage Inspection
in the Electrical System chapter.
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 connector ...
Exploded View
HG: Apply high-temperature grease.
HO: Apply heavy oil.
L: Apply a non-permanent locking agent.
MO: Apply molybdenum disulfide oil solution.
(mixture of the engine oil and molybdenum disulfide grease in a weight ratio
10:1)
R: Replacement Parts
Specifications
Special Too ...
Idle Speed Control Valve Actuator Resistance Inspection
Turn the ignition switch to OFF.
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the idle speed control valve actuator connector
[A].
Connect a digital meter to the idle speed control valve
actuator connector [A]
...