Originally Posted by fitxpert

I had my ECM replaced and still experienced the whine. Did a little further reading and did a little testing and realized it's the THROTTLE BODIES! Here is how you can tell if the noise is coming from your throttle bodies or ECM.

1. Pop your hood.
2. Put the car in Neutral.
3. Set ignition to ON.
4. Roll your windows down.
   
5. At this point...it should be silent.
   
6. Now put the car into gear. I usually go with 2nd. You should hear the whine start right away.
   
7. Now put your ear near each throttle body and confirm. I could hear each throttle body whining.

I had my service manager convinced it was the ECM...and it turns out that wasn't the problem. Here is a video of the noise well. Car is in gear.

Throttle Body Whine