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 connectors.
Wiring Continuity Inspection ECU Connector [A] ←→ Crankshaft Sensor Connector [B] BK lead (ECU terminal 8) [C] Y lead (ECU terminal 21) [D]
Crankshaft Sensor Circuit

1. ECU
2. Crankshaft Sensor
Crankshaft Sensor Removal/Installation
Rear Wheel Rotation Sensor Signal (Service Code 24)Engine No. ZXT00JE003023
1. Heat Insulation Rubber Plate
2. For Air Switching Valve Hoses (Place the air switching valve above the
rubber plate.)
3. For Stick Coils
4. For Throttle Body Assy Holder #2 and #3
5. For Water Temperature Sensor
6. Insert the tab into the slot.
7. For Throttle Body Assy Holder #4
8. ...
Water Pump Housing Assembly
NOTICE
Do not reuse the mechanical seal and oil seal.
Apply high-temperature grease to the new oil seal lips [A].
Press the new oil seal into the housing with a bearing
driver [B] until it stops at the bottom surface [C] of the
housing.
Special Tool - Bearing Driver Set: 57001-1129
...
Cooling System Flushing
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cooling
system. If this accumulation is not removed, it will clog
up the water passage and considerable reduce the efficiency
...