A friends sled did something like that it was a high amp draw code I think. Something about the headlight switch getting bumped and the high and low beams being on.
the problem was the sensor that threads into the front exhaust pipe was no longer working. 485 dollars later back on the sled. they did not warranty the sensor reason is that it is not part of inginition or engine
Did you check for stored codes? The 11 was notorious for the overvoltage code from the headlight hi/lo switch getting bumped. If this is the code, moving the switch to the riser block eliminated the problem for me.....or wherever it wont get bumped all the time.