Sensor Question

On the back of the block of my A1 near the oil filter theres a big like 27 mm hole/green sensor plug but on my b16a2 there isn’t one. I need to know what its for. Any help would be great.

heres a idea, you can see the green sensor.

knock sensor

Please don’t post unless you know what the hell you’re talking about. Sorry for being a bit rude, but this topic has been covered to death, the info is out there if you search. But if you post the wrong info in new threads then that’s what people find when they search since the newer threads pop up first.

Please refer any questions regarding this topic to THIS thread. Thank you.