Re: Random electrical errors
'Fraid Gremlins the word. Unfortunately intermittant electrics are the devils own arse to detect even with piles of diagnostic equipment - you only get to detect it when it's misbehaving - and they do it randomly on the road as you've discovered, not on the forecourt. There are other posts on here that swear that poor batteries/poor battery connections can couse these errors. First and easiest thing to check. Make sure the battery terminals are tight. All sorts of things happen to cars on dealers forecourts, batteries being flattened/changed round is the least of it, it might be as simple as that. Otherwise you may need to look for a faulty connection at a fuse/plug/earth terminal.
Doesn't say that in the manual