Strange noise?!

I believe that's the coolant control valve. The '07 does that after power-up. I believe it can cause a trouble code to appear, but it hasn't in my case. I read that it isn't likely to cause problems, it may just increase the time for the coolant to warm. I haven't done anything about it...I just ignore it.

 

+1 Control Valve and/or Pump. Once failed, it will raise the temps in the coolant and throw the error code.

 

Pretty much, the noise is the valve or the pump laboring prior to failure. Depending on use, it may take awhile or suddenly.

When the car is in "ON" ( not READY ) can you see the fluid flowing rapidly in the reservoir? If so, you are good to go. Once in awhile keep an eye on it. if it stops flowing in a rapid state, it is time to replace the pump and or valve.

 

I thought the coolant control valve was in the engine coolant loop and not inverter coolant loop. Isn't that right?

In more reading, I read about the theory that low engine coolant levels can cause the valve to stick. You might also check the level of the engine coolant at the radiator fill neck. It's under the large, black plastic cover across the front of the engine compartment. Just removing the few snaps on the cover in the front, passenger side corner is usually enough to pull it up a little and remove the radiator cap (only when the engine is cold). The coolant should be right up to the cap.

 

It's the three-way coolant control valve and it is in the engine circuit. Mine did that for tens of thousands of miles before it finally broke and I got the code. I got so used to it, when I replaced the valve and it was quiet again, it took a while to get used to the silence. You should probably fix it sooner than I did. If it breaks in the wrong position, you won't have cabin heat, I hear.

Good advice above about checking coolant in the COLD radiator.

 

You should have two if a HV.

The ICE ( Internal Combustion Engine ) has one and Your Electric Motor (Inverter) has one. If unsure check with your manual the reservoir locations.

Members are leaning towards the ICE reservoir. Locate that one and check the level. It would not hurt to find the Electric one too to insure it is rapidly flowing in the reservoir.

Google is your friend, PC also

 

Okay that goldish cover is your Inverter, now look to you left, you should see a reservoir with red colored fluid, is it flowing rapidly?



I hear the isolating pump noise then it stops then a light continuous hum ( not the HID hum ), right?

In order to access the ICE radiator cap, you need to remove the black cover as stated by a member.