Whenever you get a CEL.. hit the blue onstar button and get them to read the codes to you. People here can tell you what they meann.
If you are getting 44miles of of the car you are not using 1kw per 1.1miles on average. Its possible to use a lot more when you first start out, if its hot and the car decideds it needs TMS to cool the battery it may draw some power..
Then again if the 1.1miles is sitting in manhattan/tunnel traffic doing .1mph with comfort blasting, then the next 40 is cruising the parkway at 55mphs you might still average 44..