'06 jcw 20k

strange behavior.
Sometimes after topping the gas (93) i get a "service engine soon".
Sometimes it resets by it self. Sometimes not.
My scan tool reads: P0326 knock sensor
my scan tool will not clear the code.
Motor: Stock jcw factory built.
Motor runs strong, no loss of performance.
Does anyone sell a obd scan tool that will clear those codes?
Thanks for any thoughts.

 

I've found this code to be GAS related... If I run certain brands I get the knock sensor code and if I run other brands it goes away.
I run Top teir gas only and no troubles If I buy off brand premium I get the light
This will normally clear if you get better gas