Just bought it and got Inverter cooling efficiency issue.

Hi All,

I just bought 2009 Prius Base with ~147k from a used car dealer 60 miles away from my home. Car was sold as is. While driving back on highway, all the lights came on and i immediately pulled over. Turned it off, waited few seconds and started again. Now only the red triangle light and brake light. Also even after it is turned off, it is making a whir whir sound every few seconds. A/C turned off automatically after few minutes. Was driving at highway with mild acceleration. Came back and scanned with the OBD reader. Error code was Inverter efficiency issue (forgot the exact message) and accidentally i cleared it. A/C started working again after few minutes, i guess after cool down. No other driving issues. Drove 2-3 miles again and it didn't came back.

I did search for this all points to bad inverter coolant pump or low coolant. Coolant level is in the middle and it seems fan(s) are coming on (didn't check if one or both are coming on). I was planning to check the turbulence in the reservoir and since the car is still hot, i didn't open it. The whir whir sound every few seconds seems to be coming from the inverter area. Checked the car fax report and seems they replaced the coolant sensor when it was at 75k and no recall for inverter coolant pump was done.

1. Does any one tried to activate the coolant pump with the Foxwell scanner software with Toyota software pack or it needs the Techstream software ? I already have the Foxwell NT530. This is the guaranteed way to check the pump. If the Techstream is needed, which dongle / software? I also have a 2014 Avalon Hybrid with 75k on it. If it can check each fans, pump, it would be really nice. I have the factory software for my old bmw and it can control all electronics modules. I am hoping that level of control.

2. Planning to replace the pump anyway and replace coolant with Toyota coolant. The coolant pump for engine, any life span for this? Should i replace this as well? Regular cars like the Odyssey i have, i replace it at 100k with TB job.

Thanks in advance..