Was on a long motorway drive when 100 miles in my car showed up an EPC warning and the car started to limp. It disappeared after restarting the car. It was ok the next day but the following day, I had it again when I did another motorway run. Took it straight to the dealer and he said the diagnostic showed turbo  underboost issue but not conclusive. Took it dealer in prearranged slot for repair and this time it said low battery power caused it. I am sceptical about this and would like to know if this could be the real issue as I hadn’t driven it in a while. Any clarification would be great. Thx

Good morning, welcome to the forum. How old is the battery - have you had the battery fully tested?

If you could get the error code , it would offer further insight. Even after the engine light going out, the code would still be stored.

 

exactly, you need the error codes to know for sure, but I find it hard to see a link between "underboost" and battery performance especially when driving as the alternator will be running.

A dodgy battery would usually trigger lots of other warnings (communication errors) & its usually obvious during starting when your battery is bad because you get many messages on the dashboard after starting (ACC not available, ABS Error, etc etc)

Might be worth trying an Italian tune up if you can do it safely and see if it reoccurs

Hi 

 

battery isn’t that old and dealer said that the battery was fine but undercharged. 
 

What surprised me was that as said the battery was on the alternator so would have sufficient charge after 100 miles of motorway driving.

 

I will get the code from the dealer. They didn’t share it nor the repair report.

What year is your Superb - is it MK2 or Mk3? Does it have automatic stop start? How undercharged was the battery? If your vehicle is fitted with a 'smart' alternator, the battery will typically only be charged to around 75% max. on the alternator alone. 

It is a 72 reg so a mk3. How under charged they didn’t say. Looking to buy a trickle charger just incase. Looking at CTEK MXS 5.0 or a noco genius 5 as I have a EFB+ 5A battery. But don’t know if CTEK MSX5.0 will work as the noco specifically states it support EFB batteries.

I believe that EFB and AGM charging regimes are pretty similar - My Ring smart charger has two settings only - regular lead-acid and EFB/AGM.

Similar, almost identical, issue with my Mk3/72 Superb, 150PS Diesel and manual gearbox, on Friday. Bought car In January from Skoda dealer in Leicester so it's still under warranty and indeed should still have some of the original mfrs warranty assuming that was three years.

Running on cruise in fairly heavy traffic on the M6 when EPC light came on together with reduced power. Cruise disengaged and it's pilot light changed from green to amber accompanied by an exclamation mark. Stop start also seemed to have suspended itself.

Was going to stop at next services for a look/see but traffic ground to a halt and after turning engine off and on again manually with the button - keyless job - it was back to normal.

Will see how it goes on the way home on Monday and ask dealer to check it.

Hi,

If you can do a read out of DTCs or a full autoscan.

8 hours ago, 26DIPP said:

Hi,

If you can do a read out of DTCs or a full autoscan.

How would I do that?