Hello, I am new to this site and somewhat new to the gas benz world. My check engine light came on last week with no noticable symtoms. I tried to check and reset the code using the built in LED. The instructions I was following was to turn the key to the on position, hold down the button for 2-3 seconds and it is supposed to flash the code. When I turn the key to on, the LED is on continuously, and the button does nothing. I am in the proccess of building the radio shack code scanner, but shouldn't I be able to get the diagnostic module codes from the built in LED? Any help would be greatly appreciated.

thanks,
Will John
94 E420
82 300DT