tommyaudi

Hello!

I serviced the car last Friday. (not Audi) Audi A4 2018 118000km service. Drove home 2 miles. Then when I started the car the next day I got the following error message:"Adblue/DEF System error! The engine cannot be started after 1000km. See the instruction manual." (translated from Swedish)

Could it really be a coincidence that there is an error message after service? I went back and turned off the error but it comes right back up. They don't know how to fix it.

And when you googled, not many others seem to know either?

P21CA00 is the error code.

Audi wants to check the car for 200 euros..

But i found this error message came up when disconnecting the battery? https://forum.carport-diagnostics.co...-code-p21ca00/ Could it be that the workshop discharged the battery? Because they were very careful to put the battery on the charge while they solved the error codes the second time. But shouldn't that have caused the error message to not come up the second time? Or can you delete the error code in the wrong way?Anyone who knows more than the internet and might know what different options might trigger the error code?

J. Patterson

Do you have access to VCDS? This procedure worked on our Q7 when the AdBlue metering got “ confused” after I refilled it. That was two services ago and all has been fine since.

tommyaudi

thank you very much for reply!

Unfortunately i do not have access to VCDS. but maybe should get? would have been a dream if it is so easily fixed.

tommyaudi

Does anyone have any experience with P21CA00 being triggered by discharging the battery or disconnecting it?

J. Patterson

I see this when Googling code.

https://forum.carport-diagnostics.co...-code-p21ca00/

tommyaudi

Yes exactly, it was the one I linked in the first post. That's the one I hope I have. That the workshop accidentally discharged the battery but does not want to admit it. Or understand it perhaps. If you don't charge the car while you check the fault codes and then go to eat lunch, it's easily happened.

But a bit frustrating that there doesn't seem to be a solution for it. Apart from driving on and hoping it goes off by itself hehe.

Is there a way to speed up your own system to see that everything is correct? For example disconnect the battery?