Working on my P3101 and P3191. After the engine dies the throtlebody motor makes a high pitch whineing sound. Is this normal on the gen 1 prius? It did this before i cleaned it, and continues after.
Funny, I had never really noticed it in my Gen 1, but it's really prominent in my Gen 3 whenever I'm working under the hood. Yeah, the ECM holds the throttle in the selected position by sending a train of pulses to the throttle motor, one direction or the other. The pulses are at a frequency you can hear.
It might not be very noticeable to most people. I used to tell my maint crew at work when a florescent ballast was about to go out because the high pitch sound they make hurt my ears. Of course they tough I was nuts, but after they saw I was right about the first couple they just started replacing them any time I complained about one.
