I recently bought a 2000 A4 Quatro Avant with a 2.8 V6 and auto trans. Love the car but within a few days of ownership the CEL came on. I brought it to an independent shop and they told me it needed two oxygen sensors and possibly new converters, but they wouldn't know that until they replaced the sensors. I had them replace the sensors but within a day or so the CEL reappeared.

I next took it to an AUDI dealer for diagnosis. They said they found some cracked vacuum lines, which they replaced and that the # 1 O2 sensor on bank two (drivers side) was bad. I went to PEP Boys and bought an OEM sensor (bosch) and replaced it myself. CEL did not budge.

Question; do I need to have the error messages cleared make the light go out or should it have on its own?

I will take it to auto zone to have the codes read again within a few days, if need be.

Any feedback would be greatly appreciated. Thanks.

 

Generally you'll need to have the codes cleared. At least that's been my experience.

 

Thanks! is there any way to do that myself (I think on older cars you could disconnect the battery for a time but not on newer cars)? If not, can I have Auto Zone do it?

 

Any emissions-related code will need to be manually cleared. If the guy at Auto Zone is cool he will clear it but generally they won't - they're risking a $10,000 fine for doing so (which to me is bullshit, but it is what it is).

 

You can get an OBDII reader at Advanced for around $50 and just clear them yourself.

 

I've seen several OBDII scanners on the market like these

Home Page > Search > Vagchecker - ECS Tuning Inc

obdII scanner - Google Search

How well do they work? What should we look for when buying?

I too have a stubborn O2 sensor CEL as well that I've been battling off and on for several months that I'm looking to resolve

 

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This is very helpful, thanks. Considering the Audi dealer wants $100 just to diagnose I would say buying the ECS Pro scanner is money well spent. Unfortunately it is currently on back order.

 

In a pinch, you can disconnect your battery and touch the positive and negative battery cables together. This will reset your ECU and clear any engine codes, but will NOT clear airbag codes. Like I said, this will work in a pinch (like if you need to pass emissions inspection ) but is a bit harsh to be doing all the time. A bit like turning your computer off by unplugging it.

 

Well I might just give that a try beings I am out of time for having it inspected (was supposed to be done within two weeks of having it registered). Thanks CCA4.