Help! Which O2 sensor do I have? 3 or 4 wire?

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May 31, 2008 | 09:19 AM

98Quattro

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From: Edmond, OK

Help! Which O2 sensor do I have? 3 or 4 wire?

I have a 98 2.8L Quattro. NOt sure which one I need and I need to have my pre-cats replaced.

Thanks.

May 31, 2008 | 09:38 AM

JoeCaymanBWI

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From: Phoenix, AZ

Good luck | I had the same post 3 days ago and no reply.

I went to my Audi Advisor and asked.
My 02 3.0 O2 Sensor has 5 wires - $245.00 each. OUCH.

May 31, 2008 | 10:30 AM

4Driver4

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Kind of a silly question, IMHO.

Who cares how many wires it has? Oxygen sensors, like all parts, should be purchased based on part number. All four wire sensors are not the same.

May 31, 2008 | 10:31 AM

4Driver4

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"I need to have my pre-cats replaced."

Where are you located? No pre-cats on any US model 1998 Audi's.

May 31, 2008 | 10:38 AM

98Quattro

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From: Edmond, OK

It does matter how many wires it has....

A 3 wire O2 sensor won't plug into a 4 wire connector and vise-versa.
And according to every site out there...my 98 2.8L has 2 pre-cats and 2 post-cat O2's.

May 31, 2008 | 10:40 AM

4Driver4

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OH! You mean pre-cat O2 sensors. Got it. Again, go by part number, not wire number.

May 31, 2008 | 11:05 AM

frankinstyn

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From: Tacoma, WA

Re: Help! Which O2 sensor do I have? 3 or 4 wire?

That depends on whether you have the AHA or the AFC engine. The 30v newer engine is most likely (AHA) in which case you need the four wire oxygen sensor.

You can purchase them new here for about $100 for the front and $130 for the rears. Be sure to read the description as while they are interchangeable in the front, they are not in the rear (side to side I mean)<ul><li><a href="http://www.autohausaz.com/search/product.aspx?sid=gwtmxdu4435dzs554ablw0em&make id=800002@Audi&modelid=1313513@A6%20QUATTRO%20 &year=1998&cid=oxygen@oxygen&gid=5132@ Oxygen%20Sensor">Autohausaz - 1998 Audi A6 Quattro