another cooler problem

It looks like the temperature sensor you installed is faulty or bad connection or bad wiring.

DTC | P1118 | Coolant Temperature Sensor Circuit High For Coolant Heat Storage System

HINT: Although each DTC title says "Coolant Temperature Sensor", these DTCs are related to the coolant heat storage tank outlet temperature sensor.

HINT: If the ECM detects the DTC P0115, P0117 or P0118, it operates the fail-safe function in which the engine coolant temperature is assumed to be 80°C (176°F).

 

Thanks, I will replace it, but how come no "check engine" light? At least during short tests. I haven't driven it yet

 

There should be according to the manual. It should set the MIL (Malfunction Indicator Lamp) aka CEL (check engine light), so, can't help you there. Is your MIL working? Covered over with tape?

 

Maybe the wiring harness connection to the thermos temp sensor is broken. If the fault code remains after you've tried to clear it, then there is a problem. Don't worry about why the check engine light is not on, it may not come on until the car has been driven for a few cycles after you have attempted to clear the fault codes.

 

Ok thanks. Pretty sure MIL is fine. It worked the last time I ran the engine before replacing the sensor

 

It turns out that I was clicking on reset on Torque pro and since other codes have been deleted automatically, I thought that was all I had to do. Now I know there is a "clear faults on ECU" in the menu. All codes are cleared now, however my new question is: What is the normal coolant temperature while running the prius. Now that I have the OBDII and Torque Pro. I was driving the Prius today while monitoring the coolant temperature, no fault codes and no check engine light but I saw the coolant temp as high as 180 ! well past the max. It would go as low as 155 with the heater ON... but with the AC it was very high. The outside temperature was 80. (Miami winter day ) I am thinking there ia air in the system.... will check levels tomorrow with engine cool. Actually p1116 showed up once but it went away after I cleared and did not come back...

 

The engine thermostat is rated to open at 82 degrees C (180 degrees F) so if you are seeing coolant temp of 180 degrees F that is quite normal especially if ambient air temp is 80 degrees F.

 

Great! Thanks! All good then.