What could cause a very slight, high-pitched noise that gets higher in tone with the press of the gas pedal? Even if I turn the radio off, it is there. It doesn't matter what mode it's in. I did not have the noise with the previous factory JBL radio (Toy Highlander 2006). The unit is grounded to the chassis. All functions work properly, including the pin hack. I do have the HD radio unit installed as well, and the backup camera. Thanks for any thoughts.