Went to autozone, and...
The code indicates the following probable causes:

1. Knock sensor defective
2. Check connector and wiring to sensor
3. Engine mechanical condition - knock or rattle in engine
4. Low fuel pressure

After the SES light came up 2 nights ago, I've been hearing this rumble from my engine compartment similar to the rumble from a diesel engine.

joey1320 said it might be the knock sensor. Anyone had any similar problems? Please write your outcomes/cost.

 

well the noise is not coming from the knock sensor, the code is.
can you post a vid of the engine runing/rattling?

and like i had posted in the other thread, is there detonation?
do you have a "S", is your supercharger making the noise?
can you check your spark plugs for signs of detonation?

how do you know you have low fuel pressure? and if you checked with the pressure gauge, what was the pressure?

 

Sometimes it's the simple things..........
The SES light on my wife's 02 MC went off and I quickly took it to my MINI mechanic.
When he checked the code the first thing he did was check the fuel cap. Apparently the last time the wife topped off she didn't tighten the fuel cap all the way and it threw the light.
The mechanic even pointed to the warning written right on the fuel cap. He explained that one of the faults identified on the code was Low Fuel Pressure which can be caused by a loose fuel cap. He reset the light and told me to come back if the light went off again.
Although somewhat embarressed, I was relieved that he sent me away without a bill.

Motor on!