My a6 has 72,000 on it. the check engine light came on the other day .The car seems to run fine .Any ideas ? I disconnected the battery over night and it stayed off for about a 1/2 a day.

 

Over filled gas tank or gas cap off or lose. Maybe just a start and I am out of ideas. Might have to go get it plugged in.

 

thanks I dont think so but thanks

 

The best idea is to go to some auto store and buy ODB2 reader. It will tell you what this is.
On a6 most common is:

Fuel recirculation plug - on top of the air intake - unplug and plug again
Vaccuum leak - left side by the windshield washer container - check hoses
Loose fuel injector wires - unplug and plug again
Old spark plug cables - replace
Wet plugs on cables and wires - buy Ignition Spray and Go, spray on plugs to dry them

Do not disconnect your battery - the computer has memory that is not affected it.