I have a 2008 LR2 that runs great but after a short drive to the hardware store it won't start until I short the battery cables for a few seconds. When trying to start before shorting cables after inserting the fob, there is no activity at all. No click or any noise from the starter. After shorting cables it starts right up and will run fine until the next trip. I suspect an ECU problem but not sure. Is it an easy swap to replace an ECU or are there some other things needed when doing this?