I just bought a '96 A4 Quat 2.8. When I got it the CEL light was on and the code indicated an O2 sensor. The first time I filled the tank (Chevron Plus) the CEL went off within 20 min. Should I be concerned about the O2 sensor? Could the gas have affected the reading?

 

C'mon guys someone help a girl out!

 

What code was it? If they're ogirinal they probably need to be repalced as )2 sensors switch slower and slower as time goes on.

 

I'll have to check what the exact reading was, but I know it was an O2 sensor. One of them was changed a year ago...does the code indicate which O2 sensor needs to be replaced? Does it make any difference that the CEL turned off?

Thanks for your help!

 

Usually I repalce the O2 sensors in pairs. When one fails the other probably isn't far behind.

The code will tell you which O2 it is. Also, jsut because the check engine light turned off doesn't mean the problem has been fixed. The CE light probably won't stay on indefinitely for a worn out O2 sensor because it is still switching, just slower than a new unit.

 

if the CEL turned off there is no problem, how the hell did you know it was the o2 sensor my car doesn't have any special display for this

 

i think she scanned for codes...

I dont even use my secondary 02 sensor..... its in 2 spark plug non foulers right now.

 

you cant not use your secondary 02 sensor its computer controlled

 

what do you mean you cant not use it? You mean without getting a cel? or???

 

if the 02 sensor is not there it will throw the computer off.

and i would change the o2 sensors depending on how much milage you have on the car

milage??