Whilst tanking up the M5 yesterday evening, my tuning box decided to give up the ghost whilst overtaking a rather long lorry! I managed to get it onto the h/s and it just sat there in limp home mode

Normally a switch off and wait a few mins sorts it out, but this time it didn't. I ended up removing the box but on restarting it was still in limp mode.. The only way to reset the car was to disconnect the battery!. This worked but on restarting I found that I had no heating!! WTF!.. the fans were blowing and there were no odd noises so I'm totally confused...

any ideas?