Recommended shop manual? 2020

A5/S5/RS5
#1

Hey guys been having a mild issue with O2 sensor readiness. As of now, no cel or engine fault registered. However whenever I run the VCDS readiness, I get a fail on the O2 sensor. Don’t remember the exact message and it doesn’t say which sensor.

I’m planning to start learning about VCDS so trying to decide on the best shop manual to point me in the proper measuring blocks and their recommend values.
Last I read Erwin.audi.com was the recommendation but is this still the choice to get the most comprehensive way to work and troubleshoot the RS5?

Also What is UDS protocol?

Added: gas mileage on the info panel averages 14.9 in town and 17.8 highway.

Thanks for the contribution guys!!

Added: 2013 RS5

#2

This not a direct answer to all your questions I guess, but I can say this: running lean will show CEL(solid not flashing)–not actual lean in my case, but E45 or higher ethanol content. After I updated the software and NAV map, I would occasionally get a fault related to the software versions–that has not resurfaced for a long time now since the last time clearing faults.

The point is I think it might gradually disappear. You might need to give it a couple of months or a bit more, though, based on my experience.

Your fuel economy is standard for an inspired highway driver or one on and off stuck in traffic jams; if it was abnormal I think your CEL would have come on. It adjust automatically to all the way up to E85 increasing 25-30 %.

#3

What kind of car do you drive Tonto?

#4

I think it would help to post the year and model of car. B8.5, B9, 3.0t, 4.2, 2.9t

#5

B8.5 RS5 stock.

#6

Ie no flexfuel or e85 remap. It takes a while after you’ve filled it up with E85 for the CEL to come on (varies) and it takes a while for it to go out after you have refueled with gas/petrol; normally a restart or two–if you don’t clear the faults that is.

#7

Ahh. I only asked because I didn’t know the RS5 would work with e85 etc.

#8

If you tested with e85 you would be able to confirm your O2 sensors are working properly.

Maybe you can trigger the O2 sensors to change their trajectory a bit and stop throwing the fault also. It seems the RS5 likes a bit of alcohol, if not hard, but mixed. It is O2 sensor only as you know, but it won’t over compensate: the consumption lands where it should based on the energy content.

As it is a naturally aspirated high compression engine with direct injection. Makes me think methanol/water port injection would have more limited use compared to other setups whereas the actual fuel cooling effect and higher octane (up to a limit) might make a noticeable difference on for instance revving out. Ethanol absorbs more water which in this sense is an added bonus.

I’d say, in summary, because ethanol is said to break down the titanium or other lubricants in the oil, use it when pushing the vehicle, in order to not have to change the oil more often.

Maybe have a bit more in the mix in city on hot days to minimize heat soak.

#9

E85 and our injectors do not play well together. I’d keep it at E40 or lower.

UDS is for, if I remember correctly, pre-OBDII cars. Just keeps the VCDS backwards compatible.

#10

Also…shoot me an email. I’ll give you a copy of the FSM in PDF format. redmistracingllc@icloud.com