[changus]

I have a 95ti and I can tell you that it does have them. I say them becuase I recall the dealer's mechanic telling me that there was more than one, two if I'm not mistaken. The knock sensor keeps your car running smooth during advanced timing when the timing is slightly off TDC , you can often hear the knock or pinging sound like rocks in a can such, as when you use cheap gas and the car shutters. The sensors also keep your spark, the air-fuel mixture, and valve opperation in sync by sending signals to the computer. If your knock sensors are not working you can damage the engine components like the pistons, valves, spark plugs and more. I too had the code appear when I took mine in for a routine diagnostics, I was quoted $900 by the dealer and $600 by another BMW service shop. I didnt have it done becuase mine ended up being from my wife putting 94 octane in the gas along with gas treatment that bosted the octane another 4 to 5 octane. Basically It was damn near like running StreetBlaze race fuel. After the next refill of 93 octane my code cleared, but my solution may not be yours. Good luck and keep us posted.