I have a 2009 Mini Cooper S and the code is showing that the knock sensor is bad. I've seen on-line that it says that you need to take the intake manifold off to get to it. I just replaced the lower O2 sensor tonight and noticed that i can see the knock sensor from underneath and even touch it. Has anyone replaced this sensor from underneath without removing the intake manifold?

 

Yes you can get to the knock sensor from underneath the car. It's very difficult to do it that way. But it is faster. However the intake is very easy to take off as long as you can get to the mounting bolt that's underneath The backside of the intake you have to go through the passenger side wheel well to get to it and you can barely see it. It's a 10mm bolt it was very hard for me to find the first time but if You're able to find that bolt it's easy to remove now it takes me about 10-15
​​​​ minutes to remove the manifold.