After popping CELs for the pre and post cat O2 sensors being below threashhold limits, I decided to replace them. Only thing is, I have never done this on a Audi. I have installed a O2 sensor for a A/F on a Civic and replaced one (post cat) on a Sport Trac, and would assumme it's the same process. Problem is, I have no Idea where they are on the Audi or what I should look at spending on it. I was poking around and noticed the cat, at least that is what it looked like, under the hood, so both O2s have to be somewhere close by. How much of a PITA is this gonna be? I got some bug paws and and I have a feeling that some things that require small hands, which looks to be a lot with how packed that engune bay looks, will have to be done by someone else. Am I goning to need to get a special Sensor from Audi that takes a week to get here? What should a delear charge to do both?

I have a 00 A4 1.8T Quattro Tip. 164,496 miles. Black. And no power what so ever since the CEL came on. I have 0, and I mean 0 acceleration, no power adn forget about climbing the hill on the way to work. 50,000 fully loaded Semis pass me going up hill in second gear and losing speed. One of these days I am afraid that I am going to lose all forward momentem and get stuck. Now that would suck.

 

My car is a 2002 but I'm pretty sure the setup is similar. The pre-cat sensor can easily be accessed from inside the hood. You can see it here in this pic, right by the turbo inlet pipe (I was doing a leak pressure test).



The post cat sensor is a little harder to get to. If you follow the instructions in this post I wrote about inserting a O2 sensor spacer, it will tell you exactly how to get to it (again let me remind you that the 2002 might differ a bit).
http://www.audigeeks.com/forums/index.php?topic=2167.0

The sensors can be bought at any auto parts store, they come with a plug so that they can be inserted in the car's harness without a problem.

Good luck

 

The only hard part about replacing 02 sensors in a 1.8T is that they have a tendency to be stubborn son of a b*tch's to unscrew. I suggest getting some bolt/screw loosener from autozone before tackling the job. Oh, and the one in back of the cat is fairly hard to get to. You'll have to get some torque on it to get it undone, and I suggest getting a ratchet on there and using a crow bar for leverage to unscrew the sensor. Be careful with this method though, don't use *too much pressure with the crowbar in case it slips.

You can buy a special socket that slips right on to the sensors to help give you more loosening torque...autozone will probably have this as well. good luck, you'll notice a huge difference in engine performance once replaced!

LampyB.

 

what were the codes? why do you think its the O2 sensors? it could be a blocked cat or exhaust

 

P 0211, and P 0422. I am not at the car and going on a 3 day old memory, but I think that those are the ones

 

P0422 is the cat an P0211 is a sticking injector so I would go with the later because it over fueling

 

So you think that I would be better off replacing the injector(s)?

 

Ok, I havn't been able to duplicate the P 0211. I keep getting the P 0422 which is Main Catalyst below threshold (bank 1). My scanner also captured some freeze frame data for the DTC. It is:

DTC- P0422
Fuel Sytsem 1 Status- Closed
Fuel Systme 2 Status- Not Supported
Calculated Load Value- 19.22%
Engine Coolant Temp-195.80 *F
Short Trem Fuel Trim- Bank 1- (-)1.56%
Long Term Fuel Trim- Bank 1- (-)3.91%
Engine RPM- 2280 RPM
Vehicle Speed Semsor- 59.65 mph (96 K/HR)

Can anyone use this to help me out. I hope that it's not the cat. That would be very expensive.

Additionally, can you explain the information contained in the Freeze Fram data?

 

where can I find that little filter in the pic? I need one badly.

 

Hey, if thats not a thread jack, I don't know what is. Anyways, thanks for the free bump.