Power steering fault

[Paul cairney]

A6 c7 comes up with do not drive steering defective tpmfault ems ems fault does it need new steering rack car starts and runs ok but no power steering then its ok for a while then same faults thanks

[Magnet]

Hello Paul, 

Thanks for being in touch with the forum.

These faults can be typical of a below par battery - even though it starts the car OK.
That would be my first port of call if it were mine.
It would be best to get as sophisticated a test as possible carried out. Not sure if Halfords testing kits would be adequate, but might be a good place to start. 
If it is found to be below par, would I replace it with a Halfords battery ??
How old is the battery, and what make is it? 
Kind regards,

Gareth. 

[Paul cairney]

Thanks will check the morn saturday but would that stop power steering from working

[Paul cairney]

Battery is fine so not sure what to do with her used to love this car now im starting to hate it 

[Stevey Y]

3 hours ago, Paul cairney said:

Battery is fine so not sure what to do with her used to love this car now im starting to hate it 

Hi who came up with the immaculate diagnosis that the battery is fine, the times I have seen this and when the car is plugged and scanned it throws up a load of non communication faults caused by low voltage, you really do have to have it plugged in and check the date on the battery, the electronic steering uses a lot of voltage.

Steve.

[Magnet]

Very interesting Steve. I was minded to make a similar comment on the validity of the battery test. 
A family member had a JLR vehicle from new, and when it was 3 months out of warranty, the stop/start stopped working! 
Two battery tests with sophisticated testing equipment showed the battery to be serviceable. The vehicle then went to a well respected local JLR independent who tested it on JLR diagnostics, and it failed the cold cranking current parameter - even though the car always started without issue. 
Rather sceptically, we renewed the battery with the equivalent Varta, and hey presto, all was well again. 
Kind regards,

Gareth.