Oxygen Sensor part sourcing.

[Mark]

Threw the following fault:

16804 - Catalyst System; Bank 1: Efficiency Below Threshold 
            P0420 - 002 - Lower Limit Exceeded - Intermittent - MIL ON

found that ECS has both O2 sensors for 250 shipped (for both) . . . anyone else have a deal on both pre and post cat oxygen sensors? I figure I might as well replace both.

here's a good article on testing each sensor.

Testing O2 Sensors on AW

[CO AVANT]

I see no need to replace your post cat sensor other than spending more $$$. Even though I replace shit all the time that doesn't necessarily "need" to be replaced.

400HPA4 and A4ringedONE8t now sell oem parts at a discount, might want to PM them and ask for a price. I got mine last year through ecs as well.

Good to see you're still around Mark

[Mark]

yeah, I thought about just replacing one . . . I'm going to check the resistance of the sensors this evening to see which one has kicked the can. The thing with these sensors is that they work in a pair together, reading pre and post cat. Let's face it, both are pretty farken old at this point (79k miles) . . and with mods I can only guess that the second one is on it's way out soon anyway. Might see an increase in mileage.

did you replace both or just one?

another question . . . why aren't these under the 100k emission warrenty? (or are they?)

yeah, I've been really busy with all sorts of stuff. I've been posting off and on but not like it used to be. BTW . . . the 2.0 BT must be treating you nice, even at elevation.

[k0mpresd]

I see no need to replace your post cat sensor other than spending more $$$.

i think you mean pre cat. the code he has up there is for catalyst efficiency. which would have been measured by the rear o2.

just get a spacer and a test pipe. and call it a day. :p

[CO AVANT]

i think you mean pre cat. the code he has up there is for catalyst efficiency. which would have been measured by the rear o2.

just get a spacer and a test pipe. and call it a day. :p

yes thanks for the correction I just read "bank 1". Always thought bank 1 was pre cat and bank 2 was post cat. Damn I've been skipping over shit the last couple days on certain threads lol. Billing week makes my mind mush Yeah I replaced both Mark.

[Mark]

I though about a spacer, but I really want to keep the cat in there instead of replacing it with a test pipe. If anything I'd go hi-flow cat, but that's not an option at this point due to money constraints. Figure I'd spend only what's necessary to not throw a code and pass PA emissions at this point.

P0420 - 002 fault . . . the 002 part usually means the post cat sensor (rear), so I agree that's probably the one. I'll make sure of that tonight.

cool Jordan, I might go and do both . . . not sure at this point.

[CO AVANT]

cool Jordan, I might go and do both . . . not sure at this point.

The pre cat sensor can sure take a beating IMO. I used leaded race gas for 2 years and accidentally crimped a side while tightening down last summer. So when I replaced it I tested both sensors (new & old) in block 031 lambda and specified vs. actual were the same on both sensors.

[Mark]

The pre cat sensor can sure take a beating IMO. I used leaded race gas for 2 years and accidentally crimped a side while tightening down last summer. So when I replaced it I tested both sensors (new & old) in block 031 lambda and specified vs. actual were the same on both sensors.

good to know, mine probably doesn't get the same beating. . . just slighly more wear and tear then usual . . .

if the rear one is the only one that fails then I'll just get it and call it a day.

[edwardabodnar]

I recieved a letter from Audi I would say about 6-12 months ago and it was to inform me about a recall on the O2 sensor. I dont remember the details of it since I havent had any issues concerning it. Try searching or asking around about it, maybe you can get it replaced for free...I will dig around for it I know I saved it, If I find it I will scan it and post it.

[04QuattroTurbo]

I recieved a letter from Audi I would say about 6-12 months ago and it was to inform me about a recall on the O2 sensor. I dont remember the details of it since I havent had any issues concerning it. Try searching or asking around about it, maybe you can get it replaced for free...I will dig around for it I know I saved it, If I find it I will scan it and post it.

Hmmm. I didn't get one, I got one on the keys though. What year is yours? Maybe the 2004, is not included in the recall? I don't see any recalls posted for my car on the net.

[k0mpresd]

yes thanks for the correction I just read "bank 1". Always thought bank 1 was pre cat and bank 2 was post cat. Damn I've been skipping over shit the last couple days on certain threads lol. Billing week makes my mind mush Yeah I replaced both Mark.

"bank" refers to which side of the engine the sensor is for. im assuming this is a 1.8t. so there is only 1 bank.

[Mark]

I recieved a letter from Audi I would say about 6-12 months ago and it was to inform me about a recall on the O2 sensor. I dont remember the details of it since I havent had any issues concerning it. Try searching or asking around about it, maybe you can get it replaced for free...I will dig around for it I know I saved it, If I find it I will scan it and post it.

really . . . this I have not heard at all. I'm still not sure why the O2 sensors do not fall under the emission warranty. They should, no?

from a google search regarding AoA 2002 my A4 warranty.

The Exhaust Emission Warranty covers corrosion-related parts for 2 years/24,000 miles, plus 8 years/80,000 miles on the catalytic converter and any on-board diagnostic device

so does that mean it's covered? Is the sensor not part of the on-board diagnostic device?

just called the dealer . . . no go . . . covers the CAT and ECU only.