Lexus Shutoff Noise

[MaximaGuy]

The lexus in the signature has a buzzing/rattling noise after shutting off the engine, its my wifes car.
OOO in Los Angeles so there is no way for me to diagonize the noise source but opening a thread in any event.
Unsure until I head back home but then it is scaring my wife and making me uncomforable here out of help.

 

[JamesBond]

Is the noise in the cabin or under the hood? Sometimes hvac doors open or close when the car is shut off. Maybe one of the door motors is stripped.

 

[MaximaGuy]

Its under the hood and not encouraging since it is new sounds.
Unsure what to make of the sounds

 

[user52165]

Heat shield cooling down?

 

[WylieCoyote]

I've owned several cars that did this. It was explained to me as the throttle body going through a shut down process.

I wouldn't worry about it. If it had a problem, you'd have a CEL by now.

 

[nthach]

It's the DBW doing its shutdown routine. And even older Toyota products will make some ticking/snapping noises if you listen to the engine immediately after shutdown - that's the sound of the IAC valve's stepper motor homing itself for the next startup.

 

[MolaKule]

Well, as other's have stated it may be the cat and exhaust heat shields popping and snapping as they are cooling down.

Does this vehicle has heated/cooled seats? Believe it or not, those heating/cooling mechanisms make a buzzing noise and sometimes sounds like a fan winding down.

 

[MaximaGuy]

I finally got to it and didn't determine anything abnormal, though the battery contacts needs some cleaning.

The vehicle starter is hesistant and then finally cranks and turns the motor, not sure what to make of it although I may run it with premium gas for sometime to determine it isn't gas or the fuel path.

Any thoughts on a hesistant starter.

 

[PimTac]

It could be the starter itself, the wiring or the ground or it could be the battery.