I'm pretty dumb when it comes to cars haha and I figured the only way to learn is start at easy fixes that way I can start learning about my car. I have an 01 Audi A4 1.8t FWD and got the p0171 check engine light recently. I cleaned the MAF and made sure that was good (huge learning experience for me and enjoyed doing it very much) I got a smoke check and diagnosed by a local place for two vacuum leaks and a bad upstream o2 sensor. I want to do this myself, learn, and not pay 400 for parts and labor. I just need some help making sure im doing everything right. Which one do I need? 4 or 5 wire?

http://www.autohausaz.com/search/pro...xygen%20Sensor

Im pretty sure it's the 5 wire. I took a picture of the area i thought it was in please let me know if i'm right.



This is a pretty easy job right? Just swap it out? Whats the best advice for doing this job. Any input would be very helpful thank you.

 

your best option for the 4 or 5 wire question is ask the dealer, just be like hey i have a bad upstream o2 sensor and i need to know which one to get cuz there is a 4 and 5 wire option and i wanna get the right sensor... they should help u out there

 

I think the O2 sensor could be 4-wire - at least that's what all the replacements are listed as being (even the direct fit ones). Just buy a direct fit one and you'll be fine. I get mine from www.rockauto.com though you can go to Autozone/Advance/whatever if you need it soon and don't mind paying more.

It varies. If it can be easily gotten out, it's an easy job. The best thing to do to get a stuck one out is to hit it with Kroil (which is much better than Liquid Wrench and PB Blaster, which are in turn better than WD40), wait 10 minutes, repeat this cycle 2-3 times if it looks bad, cut the wires near the sensor (unplug it first though), and use a 22mm regular deep socket to get it out. For the replacement, use a specialized O2 sensor socket with a slit down one side to put it in. Use anti-seize compound on the threads.

Why use a regular 22mm deep socket and not the O2 sensor socket to get the old one out? The slit down the side of the O2 sensor socket will let the socket flex a little bit, and if your old O2 sensor is stuck then it could flex too much and slip, rounding the corners of the sensor. Bad!

Ideally you want a 24" 1/2" drive breaker bar for an O2 sensor.

 

the 01 is a wideband sensor which is 5-wire.

if you take the airbox and everything out, all you need is an O2 sensor wrench ($7 at autozone) and the socket wrench and extension to go with it. spray some WD40 on it an hour or two beforehand.

 

Ahhh, I was looking up for my 2000. That'll do it. Ghost's simpler method might work for getting it out, but I would still use something better than WD40, like Kroil*.

I have personally experienced the O2 socket messing up the sensor due to flex, so I won't even take the chance anymore if there's rust.

 

Thanks guys for all the help and info. Give you guys a update. I found one in my local area for $155 OEM. I dont mind spending a little more since I wont wait time to get it in the mail. It is the 5 wire and i'm gonna go pick it up from autozone right now woot woot

 

So I guess I have a split year 01 so the precat was actually a 5 wire. It was weird because all the websites suggested the 4 wire even autozone did as well. Just in case any of you wanted to know. Was really easy to install. check engine went away too

 

bump.. so i just found out i need a new turbo FML so can you guys give me the low down on where i can get a cheap stock turbo besides the stealership?

 

I sometimes see used k03's go for around 100 in the classifies on vortex or audizine.

 

Stock? But why? These are those rare but fortunate times where you can justify an upgrade! The convesation goes something like this:
"You see, Honey, for only $XXX more, I can get this great upgrade, which is something I wanted to do eventually anyway. So honestly, we're saving money in the long run if I just do it now..."
Oh course, it helps when she's in a really good mood, and you're on her good side...