Why does my Audi A4 emit a high-pitched squeal when I accelerate?

I recently purchased a used Audi A4 and I've noticed that when I accelerate, there is a loud, high-pitched squeal coming from the engine. Any ideas on what could be causing this issue?

It is likely that your serpentine belt is worn out and needs to be replaced. This can cause a high-pitched squeal when it rubs against the pulleys. I recommend getting it checked and replaced by a certified mechanic.

Another possible cause could be a faulty belt tensioner. This could cause the serpentine belt to slip and create a high-pitched noise. I suggest taking your car to a trusted mechanic for a proper diagnosis and repair.