Hello, I've had a P1116 that comes and goes for about a year now. Here are the things I have done to address it: New engine water pump Replaced coolant heater pump (installed myself) Replaced coolant heater pump connection and wiring New sensor for coolant pump New three way valve Replaced thermostat After all this the code WILL NOT STOP! Last time the dealer had it they suggested replacing the coolant heater pump AGAIN. There are really no noticeable symptoms or problems with how to car runs. The only thing fishy is that the gas mileage has been very low at 35ish mpg average (with winter tires mind you) and the defrost seems weak (I could be paranoid though). Any idea what could be going on? Thanks again.
It seems you've changed everything except for the components to which the P1116 relates. P1116 - Coolant Temperature Sensor Circuit Stuck for Coolant Heat Storage Possible affected areas: Coolant heat storage tank outlet temperature sensor Cooling system (clogging) The coolant heat storage (CHS) tank outlet temperature sensor is used for monitoring coolant temperature in the vicinity of the outlet port of the heat storage tank of the CHS system. The resistance of the sensor increases when the CHS tank outlet temperature is low, and conversely, the resistance decreases when the temperature is high. The changes in resistance are reflected in the voltage that is output by the sensor. The ECM monitors the sensor voltage and uses this value to control the CHS system properly. If the sensor output voltage deviates from the normal operating range, the ECM determines that the CHS tank outlet temperature sensor circuit has malfunctioned, and sets a DTC. Examples: No changes occur in the CHS tank outlet temperature sensor signal (over 1°C [1.8°F]) after a predetermined length of time has elapsed from the start of the coolant recovery. A significant difference (over 25°C [45°F]) exists between the engine coolant temperature signal and the CHS tank outlet temperature sensor signal after a predetermined length of time has elapsed from the start of the coolant recovery.
Just another possibility....There's a lot of coolant hoses in that area. I seem to remember a handful of years ago another member did a 3 way valve or something similar in that area and got a couple hoses mixed up. I don't remember what codes were coming in, but I remember it was a bit frustrating for him.
A Gen2 (US spec) has 4 coolant pumps. 1 mechanical on the ICE, 1 electrical behind L headlight for inverter, 1 electrical behind the inverter for the heater, & 1 electrical next to the CHS tank for that system. Which ones did you replace? Did you use Toyota parts from a reputable source? What scantool are you using? Most tools do not have the data or functions you need to diagnose this. Having a "fancier" scantool that can perform bidirectional controls is helpful in this type of situation. I let the car sit overnight. Turn ignition ON (power button X2 but NO foot on brake)- make sure the heater blower is off. Connect a capable scantool and select data for ECT (coolant temperature), CHS ("tank outlet" temperature), and maybe water flow valve position (3-way valve). Monitor this data while going READY. The CHS pump should run for several seconds and both temperatures should go up ( by about 100°F on mine). After about 5-7 seconds the ICE should start. What does your car do? On this capture I went ready just before frame 60 and the ICE started around 150. Posted via the PriusChat mobile app.
