Two or three weeks ago, the Bolero head unit in my Superb decided to stop working. No display although when turning it on the screen would illuminate but not show anything. Fast forward to mid last week. The car seemed a little laboured when starting which I put down to the cold mornings

This morning I tried starting it (not having used it since Friday night) and the battery is as flat as a dab. I took it off and put it on charge. According to the charger its holding a good strong charge so I put it back on the car.

I looked around the cabin to make sure I hadn't left any lights or anything on. I turned on the Bolero just to check that wasn't on already and low and behold, the unit burst in to life. All working as if nothing had ever been wrong with it.

I can't understand what's going on with it. I thought disconnecting the battery would require the Bolero to need the code input back in to it if it had been working? I can't say what caused the battery drain as nothing appears to have been left on and now the head unit is back in the land of the living, not that I'm remotely complaining about that! Does anyone have any ideas?

You only need the radio code if you put it in a new car.

 

The radio asks the CEC for the vehicle VIN.  If this is different to the last one, it then asks for the code.

 

As for your phantom drain, they're a pain to locate.  One way is to put a clamp meter on the battery and then pull fuses until the current drops off.  The problem with this is your car is complicated and it turns some things on and off by itself after certain timeouts, e.g. lights and some consumers go off x minutes after the vehicle is powered off (technically terminal 50 stuff).  

 

Perhaps start with a VAS/VCDS scan?  It will be full of codes relating to the flat battery so a reset and then check in a few days?

I'm guessing you have two issues. The first is a faulty Bolero (common complaint).

 

I got the white screen, turning off the ignition would cure it until the next time...

 

 

Skoda replaced it FOC under warranty.

 

The second issue sounds like a failing battery, again another common complaint on the Superb. Skoda have been fitting smaller battery's to the Superb in an effort to cut costs.