Thanks to all who read this.

I recently entered into an agreement to purchase a 2006 a3. It has 150000 miles. When I checked the car with my diagnostic tool, it generated codes p0420 p0430 and p0068. The dealer signed an agreement that said he would resolve the issues related to those codes. However, I spoke to his mechanic and the mechanic said he just cleared the codes. He said the dealer has driven the car a complete cycle and the engine light hasn't come on. He said the codes were codes in storage and not pending codes.

Is that possible? Does the car computer keep codes in storage that are no longer valid?

 

Yes it will. You can have a pending code and then fix the problem and sometimes it will turn off the CEL but the codes will still be stored. Was there a CEL present when you scanned it?

 

Yes. It had three codes. P0430, P0420, and P0068.
He cleared the codes and said they haven't come back. His mechanic said the car is ready for an inspection. So today I'm going down to check it out. All the test should be done. I should get a green light on my obs2 scanner.

 

If they only cleared the faults and did nothing else, the faults and MIL will most likely return. It may take a few days, but they will be back.

 

There were cylinder misfires until the car warmed up. Then no codes when I checked it again. However right before I took the car the engine, at idle, was rocking. My friend said that it was the breather valve. The dealer is replacing it. I'm wondering if tats why I was getting the cylinder misfires.

 

Yes, those breathers can cause a lean condition, poor idle and misfires. Let us know how you make out.

 

150k on an 06' thats like 25k/year hope you got a good deal!!