Nissan Trouble Fault Code P0115 Diagnosis Repair Engine Coolant Temperature

P0115 is for Engine Coolant Temperature Sensor.

you have a defective sensor, replace or test it like this:

check OHMs when engine is cool.
start engine and warm it up.
stop engine.
check OHMs again, you should see a big change, if you don't you the sensor is defective.
Otherwise, check cables and connections for good conditions