Let's diagnose the High Pitched Noise
 

With the number of people on this board and some with great expertise we should be able to pinpoint what is causing the high pitched noise problem. I believe that there are two separate problems and that is creating some confusion. The high pitched noise I hear is definitely not coming from the ecu. It is coming from under the hood at the rear of the engine. It is around
10 kh and is accompanied by what sounds like static (like a cheap 1" speaker being over driven). For those who have this noise, please turn on the ignition
(engine not running) and put the transmission in any gear (out of neutral) and have the hood up. You can clearly hear the noise and it abruptly stops when you put the transmission into neutral. It wll start up again as soon as you start to put the shifter into gear. I think it is some type of relay problem.
Anybody know if there is a relay in that location?

Does replacing the ECU fix the high pitching noise? Has anyone confirmed that?

Why don't you just let Nissan finish their investigation? They have admitted that there is a problem and that they are working on a solution.

let it die....

no need to diagnose, just call nissan and push for a tsb

That approach is really working well. The problem I have with some others has nothing to do with the ecu (presently being investigated). It is a single part located somewhere at the back of the engine that is causing the noise. If you don't want to help fine maybe someone else as an idea.

I'll try this on my G37 tomorrow and let you know what I hear. I've always suspected it wasn't just the ECU since I could hear the noise from the outside near the cowling.

Have you identified what the part is?

No, but it is at the back of the engine toward the passenger side. I took off the engine cover but didn't see anything specific.

Hmmmm! For those with the noise, are they all with SRM? Or is the issue global? I am just curious as per your description, you need the car in gear.

I admire your pursuit. If I had it, I probAbly would not be waiting for Nissan.

It is interesting that as soon as you put it in neutral the noise stops (engine doesn't have to be running). Push the gear shift slightly toward any gear and it starts up again. That should provide a clue as to what is causing it.

So do you have the SRM?

When you say the passenger side, you mean the right hand side of the car, yeah? The reason I ask is all of us with right hand drive versions (Jap, Aus, UK, etc) don't have the issue as far as I know. This may help to isolate the issue to just the American models.

I have the rev match and it doesn't have any effect on the noise.

Does this happen on any of the AT's?

Anyone else with srm with the noise? Better yet, does anyone have a non-SRM car with the noise?

This is a common issue on G37's auto or manual, and also the EX35's. It doesn't have to do with the transmission.

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:

I just tested for the throttle body noise, and I also have that on my G37, but it's really of no consequence compared to the noise I'm hearing from the ECU which is many times louder.

What's an ECU?
 

Can someone please tell someone new to the forum what an ECU is?

Thanks

Electronic Control Unit (ECU). Your cars brain / main computer.

I was very surprised when I heard this so called high-pitched noise while my car was completely turned off. I had it up on ramps yesterday and I could easily hear a high-pitched tone coming from somewhere in the engine bay. Really annoying and should be fixed by Nissan.

Weird thing though, I have been under the car before and never noticed it, so maybe it only comes on under certain conditions?

I don't know the specifics of this particular engine. But my best guess without actually seeing the problem in real life; I guess it could be the fuel pump. Maybe it's the sound of the fuel under pressure passing through the fuel pressure regulator. I have had cars the made similar noises.

The problem with warranty's is that it says in the terms and conditions that it doesn't cover out of place noises, sounds, or vibrations. So unless the car isn't running smoothly, there isn't much that can be done about it legally.

I just don't understand how an ECU could make much noise. All it is, is an integrated circuit with small amounts of electrons flowing through printed microscopic circuits and transistors. Electricity at this tiny level doesn't make much noise but lightning does. for example. If your desktop computer were switched ON but your had removed every single cooling fan and electric motor, the computer would be virtually silent. It wouldn't run for long before overheating though and I wouldn't recommend it.

I have seen many engines in my life. The relationship between humans and reciprocating engines is illogical sometimes. People start to expect too much out of them. They are complicated pieces of machinery and stuff is bound to go wrong. Considering how complicated they are, they are a whole labyrinth of moving parts and systems that are all operating independently of one another. Great is their complexity. At any moment certain parts of the engine are activated seamlessly without the driver ever knowing about it. A little noise is normal. You've got all kinds of fluids operating under pressure and at different temperatures.

Considering the great complexity of these engines. It's only natural that there would be some unexplained noises. And in some ways engines are no different than computers. Where the unit is programed to operate a certain way under certain conditions etc. Although I enjoy working with engines more then computers since it just seems more rewarding. I can't stand offices and cubicles and all the stale air inside to contend with.

A bad engine is almost like bad computer programing.

I plan on keeping up with this technical problem. I'd like to find out what it is.

No car company is perfect. Even BMW makes engineering mistakes at times. They once made a BMW motorcycle that had the fuel tank located close the the engine in such a way the the fuel inside the tank would start to boil from the high heat!

I'm still not convinced that it's just the ECU. My noise has been off and on for the last several days, and I can't seem to find the smoking gun of what triggers the event. It can be there from the first second after the first start of the day, or not at all, making me think there are other components involved. Very strange.

It was confirmed that some throttle bodies also make a high pitched noise and this is coming from the engine compartment. Not as loud as the noise coming from the ecu.

Yeah I'm pretty sure a throttle body can make noise if it had some electrical stuff in it.

Another item to look for is the ABS brake system. Those make noise too at start up. Especially during start up since the system has the reset itself. For lack of a better word for it.

My 2009 6MT has this issue, loud high pitched sound from back of engine. It does sound like a cheap distorted speaker... Weird.