P1116 on a Toyota Prius is an OBD-IiManufacturer-specific code for a voltage issue with the engine coolant sensor in that the signal being sent to the engine computer is not within the range set by the manufacturer. Second-generation Prius, model years 2004-2009, has a 3-way valve to control coolant flow between the engine, the hot coolant storage tank, and the heater core. It is involved with heating the passenger cabin, as well as reducing cold-start emissions.If anything on Prius has to do with emissions the check engine light will illuminate; if something goes wrong with this valve, the light comes on. The control valve is prone to seizing, and Toyota has issued a technical service bulletin (TSB) on this problem.
Nick
February 16, 2024
I have replaced the sensor and after a week I had check engine light on again.It shows same code.Other forums show that P1116 most likely is the sensor but could be the 3 way valve.They both send signal to the computer and sometime for the valve shows P1121 but also P1116.I did the sensor first because it takes 20-30 min and it is cheaper.
So it mean that P1116 is broken 3 way valve or brolen ECT sensor?
Donald L
July 30, 2020
The Toyota Prius code p1116 is for Engine Coolant Sensor Out Of Range/ECT Sensor Out Of Self Test Range.
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