new to ford

Hi all

New to Ford owning and have an issue. Last Saturday we were driving from Lincolnshire to London everything was fine for some 30 miles when I exited an rb there was an audible alarm and info symbol on dash followed by engine malfunction message and what sounded like a rattle /buzz for a second or two, pulled over checked oil and water. Started up again, everything fine until the next rb and the same thing happened in fact it happened at every rb until we got to the A1 then drove 80 or so miles without issue until we hit the roundabout near Bedford, again had the display and rattle /buzz, car settled down and continued a further 35 miles on M1 with no problems, arriving at our destination I called into a garage and they did a diagnostic check with a snap on code reader and nothing seems to be stored. Following day drove home everything fine, no issues until we hit a series of roundabouts near Lincoln when the issues started again, after one rb I went to overtake a truck and the engine malfunction message appeared followed by rattle /buzz but there was also a huge cloud of dirty white smoke out of the exhaust, pulled back behind truck, everything settled down and apart from the rb issues got home safely 

I have done the live data /self test on the car which threw up a couple of codes

P02-40 turbo boost sensor circuit B range/performance 

P05-05 idle control system malfunction 

P11-01 maf out of range

P01-50 oxygen sensor circuit malfunction bank 2

I guess I have 2 questions really 

1,has anybody had a similar problem as this? 

2, are the errors stored 'live' codes or could they be from previous issues? 

I have only had the car a month so this is all new

Ford Fiesta 2009 1.4tdci

Any advice would be appreciated as the garage I got it from are having it back to check it out, but will probably only use obd to check diagnostics, which of course won't show anything 

Thanks in advance 

Barry