Went into Limp Mode

[Matty Baby]

Recently had to jump a mates car, but as I was doing it the live jump lead popped off mid process and my car shut down enough to need a jump start, why is this?

Also ever since, I get random limp mode previews, the gearbox and engine management light goes on for a second and revs drop then a second later everything goes back to normal!

Any ideas? Other than diagnostics! Just a case of whacking it on diags and deleting the fault?

Thanks