My battery light kept flashing while driving, after about 3 months, my boot kept 'unlocking' (not so much opening) while I was driving, or it would start 'buzzing' (like when you've left the lights on but engine off.
After a year of this, took it to Nissan - they said I needed a new boot catch (I knew this wasn't true - as it held shut when it wanted to for months on end). Took it to another Nissan dealer, then said it was the boot switch - they replaced this for £100 and have had no problems since, and battery remaining fully charged now (clearly had been draining battery as boot kept trying to open while locked - so 'buzzed' instead.)
Just before Christmas, engine light came on - AA said it was camshaft position sensor. Turned it off and said take it to Nissan if it comes on again. Came on again, Nissan said my timing BELT had stretched and it would cost me £998. I refused to pay that, and took it to my local garage who looked at it and said 'you haven't got a timing belt, you've got a chain and there's nothing wrong with it' - they charged me £45 for diagnostics, and told me if it comes on again, it could be due to needing more oil, a faulty sensor, or the fact that you've had difficulty switching it on (3 or 4 times) and therefore has reported as a fault. Either way, nothing to worry about.