Audio 20 switches off by itself

[robaa]

My 2012 (212) E-class has the Audio 20 system fitted. It used to be so that when the engine was switched off but power left on (= key in pos. 1 or 2) the audio would continue to work for quite a long time (not sure how long, but say 20 min at least), then a message would come up saying if you don't start the engine soon the system will switch off.

But lately, it just goes off by itself, very quickly after switching off the engine (maybe <1 min?) and without any warning. And when it does, pressing the on/off button won't bring it back on, I have to switch power off (= key pos. 0) and back on again.

Any ideas what the problem might be and what to do about it?

Cheers,
robaa

 

[st13phil]

Are you using the car regularly / normally or is it spending days on end sat on the drive? If the latter, it’s probably a result of the battery charge being low.

 

[robaa]

Are you using the car regularly / normally or is it spending days on end sat on the drive? If the latter, it’s probably a result of the battery charge being low.

Huh. Wouldn't even have thought of that. But now that you ask — yes, I do use it quite little and infrequently these days, sometimes only once a week for a short local journey.

BTW, the other thing I've noticed over the past year or so is that the stop/start system works very seldom, the ECO symbol hardly ever turns green. From what I gather, the system uses the secondary battery, and I'm thinking maybe that battery is on its last legs (I think it's still the original, and the car is 8+ years already). Do you happen to know if the audio system uses the secondary battery also, by any chance? In other words, might I be so lucky as to solve both problems by replacing the 2nd battery?

Thanks,
robaa

 

[st13phil]

Stop / start inoperative is definitely a symptom of low charge on one or both batteries. Especially as the car is spending long periods standing, I’d be inclined to invest in a quality maintenance charger (CTEK or Optimate) and charge the batteries first before rushing to replace them.

 

[robaa]

Stop / start inoperative is definitely a symptom of low charge on one or both batteries. Especially as the car is spending long periods standing, I’d be inclined to invest in a quality maintenance charger (CTEK or Optimate) and charge the batteries first before rushing to replace them.

Thanks, sounds like a good idea!

 

[davymead]

Spending long periods of lazy time sat in the car during warm/hot weather I’ve observed how cleverly the system regulates my usage of the audio system to save the batteries. It’ll shut the roof too if it’s a mind.