loud constant squeel and CEL.

[ProjectM96]

You know when you let air out of a balloon and you stretch the opening to make the loud squeal? my car sounds exactly like that. the check engine light turned on about one hour earlier. the noise continues even one Idle and stopped. and the noise continues about one second after you turn the car off.

no smoke or any other issues on how it drives. acceleration on breaking feels normal.

5 speed MT.

could it be the AOS even without the smoke?

I am afraid to drive it to get the check engine light checked. I turned the car off about 10 seconds after the noise started.
Noise did not change or go away when switching gears