I have an older S4 (2000) model that I bought about six months ago.

the car drives great and the only issue I have had with it was a small crack on the Rad overflow tank, which I was able to replace myself a few months back.

Everything is running great, but this morning engine light came on as I turned it on.

The car still drives fine, no issues at all. I was able to make it to work (only a few miles down the road) with no issue.

Is there a way I can check the problem myslef. (Engine codes?) and see what the car is complaining about without going to the Audi dealer?

Thanks,
Dave

 

You need a VAG scanner to read codes.

Ross Tech VAG-COM is by far the best aftermarket option but there are also cheaper ebay type cables and basic code reading support thru older (read free) Ross Tech VAG-COM software such as v4.09. Suggest have a look at Ross Tech's website for much more info.

 

Thanks K-04

I found the site and going with the scanner.

I figure with my car it's going to be a good tool to have handy. Audi wanted $175 bucks to plug in my car and lookup a code for something that may a simple DIY project (I hope)

Cheers,
Dave

 

My guess is the emission CO2 sensor. It goes away after few days. My S4 does it all the time. It also happens when you don't close the gas cap all the way

 

Hey everyone..

Thanks for all the feedback. I got the scanner and did a scan and it came back with the following:

VAG 17831 - Secondary Air Injection System (B1) - Flow to low

So I know what it is... Is it something I could fix ?? and is it serious. The car seems to drive fine..

Cheers,
Dave

 

SAI operates only during engine warm up phase to reduce engine warm up time period emissions by pumping fresh air into the exhaust. Initial suspects for your DTC are a weak SAI pump, a leak in the SAI hose system or a fault in one or both of the combi valves.

VAG-COM should be able to real time monitor and output test the SAI.

 

^ knows his sh*t ^