iEATbabies

Hey guys new G owner here. Overall, love the car drives great and I've been wanting it for a while now. The only issue I have is a weird high frequency ringing noise when I raise the RPMs above like 1100. Doesn't matter if I'm in park, neutral, or drive, but once I raise my RPMs above around 1100, the sound comes. The car makes no noise once it is fully stopped and the RPMs drop back down. It's kinda like a hearing test noise at a really high frequency. It's not the speakers because I turned the audio off yet it still occurs. The sound is constant and does not change in pitch at any point. At any RPMs above 1100ish the car makes the noise but of course it's harder to hear at higher RPMs due to the engine noise. I hear it most in the cabin with the A/C off and windows up. Also, it sounds like it's coming from the passenger side but I can't be for sure. I feel as if the sound started after I bought the car because I didn't hear it during my test drive or even in the weeks I owned it (been almost one month since I've bought the car).

I have checked other threads and I have heard it may be an ECM issue but didn't find a real fix and those threads are pretty outdated.

Also, if it helps, 2008 G37s Coupe 5AT w/o nav and backup camera (155,000km).

Thanks.

issa9002

Hey, I have the same issue in my '09 6MT. I have been trying to find a fix since the dealer wouldn't do anything about it last year. They consulted Infiniti TechLine who said the revised ECU wasn't in production or available anymore. They offered to put sound insulation around it which would only reduce the level slightly and present a fire risk. :/ again

If you can get a spectrogram/frequency analyzer app on your phone, you should be able to see a sharp peak at a higher frequency where that sound is (there will be lots of lower frequency noise, especially if you have to be moving to get it going. If it's right at 10kHz then it's this issue. Welcome to the world of car-induced tinnitus. Some member was going to try cracking it open and upgrading ground connections he found in the ECU Factory Service Manual (https://www.nicoclub.com/infiniti-service-manuals) but he became busy, and I haven't had a chance to deal with it other than I always drive windows open and I have an exhaust. I have also heard that there were bad capacitors used instead of the bad ground theory but I have no clue.

Oh, and I did try adding the Black Betty Engine Grounding kit and I can't remember if that had any effect to help reduce the noise (I suspect not).

BeeW

Above poster is probably right, but because it's quick n easy... Check your windshield washer fluid tank, the plastic pin/clip that secures it often breaks off.
Mine caused same/similar noise at ~1000RPM and drove me nuts for a while.

iEATbabies

Thanks for the reply. Its been a few weeks and I've definitely gotten used to the noise, though it's still present. I assumed the dealer wouldn't be of much help.

iEATbabies

Will do, thanks.