I am hoping that a switch or solenoid gets triggered by the movement of the shift lever which works with the throttle. Not necessarily transmission per se but something electronics.

i too believe there is something under the hood causing the noise. the noise seems much louder and more audible outside the car, under the hood, probably somewhere near the battery area.

i have the weird noise sound as well except mine sounds like coins buzzing. i have no type of change in my car at all and i know the sound is coming from the engine bay

In the past I've thrown out the idea that it could be the xenon lights, which require a ballast. A ballast is a device that increases voltages to the levels that some types of light bulbs need to work. In the past transformers were used but more recently they have been replaced by electronic ones. One difference between the two are the frequency of the ac voltage that they use. Electronic ballasts operate at much higher frequencies, so instead of hearing a buzz or hum we now hear high pitch noise. The research I've done has indicated that electronic ballasts in cars work at around 450hz, which isn't close to the sound we're hearing. But it could be possible that the ballasts used in some Nissans and Infinitis use a much higher frequency. I'm not saying this is the problem, but it's a possibility and I'll throw the idea out there.

In the Z that I test drove the sound seemed to come from between the passenger seat area and the engine compartment and was audible at all times except when the car was turned off and during the first few minutes after being started.

After looking at the service manual for awhile, the noise problem that I have with my car
(and some others on this forum) may have something to do with the park/neutral position switch. This is a switch that obviously is designed to determine when the car is in neutral. Perhaps that is why the noise stops in neutral and starts up again as soon as you start to put it into gear. The switch itself is located on the transmission but that is not where the noise is coming from.

No offense, but we determined a long time ago that there were two different high pitched issues, one from under the engine cover (electronically controlled throttle bodies?) and one from under the right side of the dash (ECU?).

John

I know that there are two separate noise problems. The one coming from the engine compartment is definitely from the throttle bodies. Just started another thread on that.

Hmmm....how can you differentiate between the two? When I hear the noise in my G37, it's screaming loud--not something you can cover up with turning up the radio.

There are at least two different problems that drivers are encountering. The one we are talking about here can be diagnosed very easily. Turn the ignition on (without the engine running), make sure the car is in gear and open the hood. If you have this particular problem, you will hear the high pitched whine coming from the throttle bodies.

I'll try that thanks! How loud it the TB sound in the cabin...will it drive you nuts like the ECU problem, or is it one that can easily be masked by the radio?

Actually I don't hear it in the cabin after the engine starts so I guess it's not as bad as the ecu problem. I think ecu is under the carpet in front of the passenger.

I had time today to really check out the sound in my car....I have the noise coming from the Passenger side. Now when My car is parked and I hit the gas I hear the noise, then when it's idle no noise. Is this the ECU issue? Should I have them replace the ECU? Thanks for all your help!

I thought the memo from Nissan cleared this up for everyone?

An excerpt from the memo:

"...when operating the special SDPS. The SDPS or Stray Dog Protection System, emits a high pitched frequency that will deter stray dogs from running after and possibly biting your vehicle which may cause visual damage. The SDPS is designed to emit at a frequency that is not heard by the human ear however, under certain conditions and lab testing, it may be audible to certain two-legged individuals..."

:icon18: good one :tup: