So, last night I was driving with radio off and a "whirring/fan" sound was audible in the rear of my 2002 SC430 - a sound that I have never heard. The sound seemed to resonate from the driver side, access panel (which I believe holds fuses and other systems for roof). After the vehicle was stopped and restarted the sound continued. Now today, I insert the key into the ignition - no sound; turn to accessory - sound is audible; started vehicle and did not hear sound. Second time I repeated and sound was heard; started and did not hear sound, Third time I repeated and no sound heard in accessory start position. What the heck is this? Does anyone have a diagram of the trunk and what components are housed in the center bay? Does this vehicle have any auto-leveling function that activates? Inquiring minds need to know!

 

DVD navigation player spinning?

 

That was my thought - it's coming from the driver side of the vehicle toward the front of the trunk. I just drove it and it has now started back up. Roof works fine, no warning lights -- it's weird as sh+*.

 

It could be your fuel pump.

 

my thought, as well... it literally sounds like a fan

 

I believe it's the cooling fan for the subwoofer amplifier. Mine does it as well, sometimes.

 

The amp should be on the right side(passenger side). The fuel pump is on the left side below the rear seat cushion.

 

...this would be my first guess

 

I agree with the "emg2919" , cooling fan for the Mark Lev. amp. Mine did the same thing and the amp had to be replaced. There is no repair for the fan alone, a whole unit repair unfortunately.
The fan bearing is going bad. Eventually the fan will stop running and the amp will over heat.

The amp is not cheap and comes with a year warranty. Approx $900.00

My two dealerships, have never had a bad 430 fuel pump in the shop unless a wreck caused damage.

 

I was not implying the fuel pump is bad, all fuel pumps make some noises. Some louder than others and when the fuel pump ran with not so pure (clean) fuel through, it tends to make louder noises. Disclaimer: I certainly don't know if his fuel pump was the noise maker, but he did state that the radio was off and upon restart the noise was present at first then not present later, all these indicated to me that the fuel pump was functioning as normal as the situation was occurred. Then there is the location of the sound which does not match where the amp is located.

Once again, this is just my opinion and it's for others to make the correct judgments.

 

This sound continues to baffle me -- the fan for the amp and fuel pump are the top of my list now. After speaking with Lexus and having them contact a service tech, they indicated that there are no known service bulletins on this issue. Alas, a visit to Lexus or my mechanic is the future...

 

You can pop the back seat cushion and see if the noise indeed comes from the pump area.

 

If you follow the leads on your fuel and amp but don't have any results, might it be the antenna motor? I know you said driver side but it might be loud enough that it resonates in the trunk. Is your antenna functional? Does it raise up and down? If not could be the motor has chewed teeth on the mast and your getting that sound. Even when my radio is off I hear a little whirring from the antenna motor, so might be something to rule out also.

 

when the sound starts again, remove the Navigation DVD. If the sound stops then you know it is the navigation unit, if the sound continues, it will most likely be your fuel pump.

If you hear the sound when the car ignition is set to ACC, engine off, the fuel pump should not run continuously. It should only run a few seconds to build pressure.

Let us know!