Hi guys, I had a friend rub diagnostics on my car, but VCDS kept saying it couldn't access the charging system.

I have an issue with it somewhere, but have no idea what it is so was hoping VCDS would point my in the right direction. Being an apparent "Smart" charging system, I assumed it would be scanable...

Is it something that can usually be scanned, a dealer only access or trial and error to find the fault?

The car is a 2006 Octavia Elegance BXE TDi

You can view the system voltage with the engine running. This will give you an indication if the alternator is charging or not. You can also view the alternator load (in %) which should go up as you as you add load by switching things on. There may be stored codes....for instance if the load sensor wire is broken (common cause of alternator not charging). 

Well my issue is that when I start the car and for the first few mins of driving, and lights that are on will go dim, bright, dim...constatly.

When the car is in neutral it will do it, but after a few minutes, it stays constantly bright while driving...put it in neutral again and everything dims, headlights, interior, dash/clocks/climate etc.

The car is in warranty for another 2 weeks but would like to know what us wrong before the dealer fobs me off...

A couple of people have said it is to do with the smart system? I have no idea what makes it "smart"...pain in the ass if you ask me! Never had an issue with the "old fashioned" charging systems!

Battery is new and alternator is 25k miles/15 months old, so figured I could rule those out...

I have experienced the bright/dim lighting issue in a previous car. It turned out to be a very worn out battery confusing the regulator.

 

As your battery is new this is probably unlikely and It sounds like a faulty regulator on the alternator. The usual fix for this is to completely replace the alternator, which is a bit pricey on the Octavia so I'd get down to the dealer asap!