Audi A4 2016 quattro Engine start system fault

[Jose R]

Hi,I'm new here in this forum as I just bought a Audi A4 2016 2.0 TDI QUATTRO and this warning appeared on the screen. I took it to mechanic and no errors  appear in the diagnostic software machine but when he press reset errors the light disappeared for a few days but come back again. Anyone know what can be the problem? The car starts and drives fine without any noises. Thanks 

[cliffcoggin]

It is possibly the battery starting to fail. Get the battery professionally tested; do not rely on a voltage reading to tell you anything useful.

[Jose R]

Cliffcoggin, thanks for your awser. Do you know the voltage that the battery should have? The awnser from the dealer where I bought the car is that the start button should be changed as probably is faulty. Can this be right? Thanks 

[cliffcoggin]

Sorry Antonio.

I mistakenly omitted the word "not" from my previous answer, which I have now amended. You should not rely on a voltage reading to tell you about the battery health because the load imposed by a simple meter is only a few milliamps, which is not enough stress to show up internal faults. Professional testing should impose a load about 100,000 times a multimeter (i.e. about 200-300 amps which is what a starter motor draws,) in order to truly stress the battery.

[Jose R]

Hi, thanks for your awnser on this now just appear another light but no advise on the screen only the engine start system fault. Do you think is about the same as no other advice appear?

[cliffcoggin]

I repeat: get the battery professionally tested.

[Magnet]

Halfords stores will be able to test the battery for you, and I would get the alternator output checked at the same time.

If the battery tests as substandard, you would be well advised to report back before purchasing a new one, unless you don’t respect your wallet. 
Kind regards,

Gareth. 

[Jose R]

Thanks for your help Clifford and Gareth, I will go get the battery tested. One more time thanks for your advice 

[cliffcoggin]

Do please let us know the outcome in case further investigation is needed.

[Jose R]

I will, I book the test with kwik Fit tomorrow at 12pm. Are they reliable? As in HALFORDS site they said in their site that we need to drop the car and then they will give me a estimate time to go there and pick up,can take all day and this is something that I cannot do. Should I ho to a mechanic directly to check this? Just give me your advice on this as I want to do the best to my car, thanks 

[cliffcoggin]

Kwikfit has one of the worst reputations in the business. Better to go to a proper garage, preferably an auto electrical place, which will have the expertise to do a deep discharge test on the battery.

[Jose R]

The battery had 48% charging and I just put a new one, this is something that I will ask the dealer to pay me back as I have the car for only 2 weeks. I messaged him and he said a new battery was not needed but I  cannot trust on his word anymore. I done a diagnosis test as well and the engine management light on is the DPF. I will meet with the dealer next week as he is in holidays at the moment till Saturday and to be honest with all this headache I'm thinking to give the car back to him and have my money back. At the moment no lights in the dash but all the time I get in the car I'm always concerned that something wrong will appear there. Do you think that is worthing stay with the car with the DPF issue as well?

[Magnet]

So was the battery only 48% charged, or 48% efficient? 
Just wondering who tested it for you, and whether you had a print out of the result to show the selling dealer? If not, he only has your word for it needing a new battery. 
As a matter of interest, what make battery did you buy, and was the new one coded to the car? 
Alternator output checked? 
Kind regards,

Gareth.

[cliffcoggin]

Antonio.

Did you get a printed test report on your old battery? Did you code the new battery to the car? Did you reset the error code via the OBD port? Did you get the charging circuit tested? Unless you did all those actions you may well be destroying your new battery, so please provide some answers.