My 2013 A4 has started to bring up numerous faults when turning the ignition on. The first fault is a ABS fault then it brings up parking brake malfunction fault and headlight adaptive fault.

 

any ideas?

 

 

Hello Danny,

Thanks for joining the forum and posting your plea. 
Simple things first:- 

Worth getting a sophisticated battery check. 
Kind regards,

Gareth. 

16 hours ago, Magnet said:

Hello Danny,

Thanks for joining the forum and posting your plea. 
Simple things first:- 

Worth getting a sophisticated battery check. 
Kind regards,

Gareth. 

Battery tested…12.2V with ignition OFF.  13.4V with ignition ON

Is that about right?

How are you testing it Danny? 
When you say with the ignition on - do you mean with the engine running? 

8 minutes ago, Magnet said:

How are you testing it Danny? 
When you say with the ignition on - do you mean with the engine running? 

Yes so 12.2 V with engine off and 13.4 V with engine running 

 

Testing with fluke multimeter across positive and negative terminal…

Not the way to test the battery efficiency Danny. Alternator perhaps - which seems far too low an output, but you first need to get the battery’s efficiency tested under load. 
If the alternator output is indeed low, then you will need to recharge the battery on an ‘intelligent ‘ charger ( your battery is an AGM one I would have thought). Once it has been charged overnight, you can then get its efficiency check by someone like Halfords. 
You could recheck the alternator efficiency once the battery is recharged - by the same method as you have already carried out - Incase it makes any difference. You should be looking for a running voltage of somewhere near to 14.5volts. 
Kind regards,

Gareth.