98 A4 2.8 30v manual 233k.

I recently posted about rebuilding my secondary air pump. It had already been rebuilt and was trashed so I bought a used OEM. Replaced it and did some hardware store engineering to repair one of the hoses. Also replaced CEL light and that works. So far it remains off. How long does it take for it to throw a code again? I have had codes for 02 sensors and cats. Apparently a bad SAP can cause this ...
So how many miles can I expect to go before codes go up again? Does it matter how many times the car is started or not so much? Is there any science to this or does the CEL come back when I'm hungover and low on funds?
Have had excellent experiences on this site ... so thanks for that. And thanks in advance if you have any input on this (maybe) stupid question.
Peace.

 

you have to wait for the vehicle to go thru a "checklist". could take a week or two. not sure exactly but i noticed when i had a cel for my tp, it would trip after clearing a day or 2 from the date of scan/clear. so id imagine the cycle isnt that extensive.

 

Depends on how far, fast, and how long (time-wise) you drive. Like slow said, there's basically a check list that the ECU has to go through to check readiness for stuff like emissions and catalysts and so forth. The O2 sensors and catalysts have to get up to temp for a predetermined amount of time, crap like that.

TL;DR: there's really no way to tell.

 

Audi problems...

 

I'm in the middle (hope the end) of a SAI mission. you should be able to read readiness codes fail even before the light comes on, and the SAI will always be failed (except if it is really hot outside?). I've thought I was ok for months on and off resetting the CEL, but at the end of the day, I THINK it is the Combi valve now, after trouble shooting from the ECU box to the combi. After a long drive the other two codes like you have were cleared by the ecu (but not 0411). I bought a used combi, it was as bad as mine, so I broke down and bought a new one from Importec for $130, including two gaskets. I'll let yall know.

 

Thanks for the input. After doing the Secondary Air Pump I had no CEL for 130 miles and enough systems had reset for me to get a sticker.

 

So I changed a tie rod and control arm bushing, also an exhaust clamp to get my mechanical inspection. So now I have stickers! It was 30 months overdue.
Thanks very much for all the input and help.