Power/starting problem-help! :(

[TomA31992]

So my car is refusing to start.

Showing '!' And the oil symbol and the oil sensor symbol.

Called out a diognostic guy who showed up "00668 supply voltage terminal 30 open - intermittent

He reckons this means a high power wire isn't earthing, he said check the ignition barrel as he thinks it feels loose and after that just check all thick red wire.

Can anybody help me? Or experienced anything like this and know the culprit?

Please help

 

[A3-Lee]

Terminal 30 is constant love check power and fuses at the battery fuse box

 

[TomA31992]

Took me a minute to work out why you were calling me love then haha.

Will check that first thing tomorrow thanks mate!

 

[TomA31992]

Oh yea, and very occasionally the car does start.

And when trying to start it once earlier, a small amount of white smoke came out of the holes in the engine cover, not sure if that changes what it could be?