post CAT O2 sensors
Thread Starter
Audiworld Junior Member
Joined: Aug 2013
Posts: 49
Likes: 0
post CAT O2 sensors
Me again........
occassionaly my 2.7t a6 is chucking a CEL for post cat o2 sensors - and having searched on here I can see getting the wiring out is an absolute NIGHTMARE due to the clips etc.
So cos I'm a practical type of bloke and like shortcuts where possible - is it possible to use a generic 'splice in' Bosch O2 sensor and cut the wire from on top of the post cat sensor in situ - unscrew the old sensor then screw the new one in and then perform the splice from underneath with the original wiring all still in place?
This would see to me to be by far the easiest way of doing it - IF the wiring is reachable from underneath.
Second part of the question is - should I even contemplate using a generic aftermarket splice in O2 sensor, or are they junk and throw CELs for fun?
cheers
Nick
occassionaly my 2.7t a6 is chucking a CEL for post cat o2 sensors - and having searched on here I can see getting the wiring out is an absolute NIGHTMARE due to the clips etc.
So cos I'm a practical type of bloke and like shortcuts where possible - is it possible to use a generic 'splice in' Bosch O2 sensor and cut the wire from on top of the post cat sensor in situ - unscrew the old sensor then screw the new one in and then perform the splice from underneath with the original wiring all still in place?
This would see to me to be by far the easiest way of doing it - IF the wiring is reachable from underneath.
Second part of the question is - should I even contemplate using a generic aftermarket splice in O2 sensor, or are they junk and throw CELs for fun?
cheers
Nick
AudiWorld Senior Member
Joined: Mar 2004
Posts: 911
Likes: 17
also consider leaving the old sensors in and putting in spacers/extenders that will usually stop the codes for intermittent Cat warm up efficiency. Your aging cats may be triggering the code. I the extenders in and no more occasional codes(which were getting more frequent as time passed).
If your code is for the O2 sensor heater, then the new sensors are the answer.
If your code is for the O2 sensor heater, then the new sensors are the answer.
AudiWorld Member
Joined: Dec 2013
Posts: 183
Likes: 0
While I've never posted on here, I have prowled the forums for sometime now since my semi-recent Audi purchase... Also, I realize that my question has been asked many times before, and I've searched multiple forums and read at length regarding the O2/cat debate (as far as which is to blame for my particular code) but I couldn't find any specific info regarding whether a spacer would alleviate the problem or not.
The code I'm getting pretty regularly, especially since it has gotten colder (maybe that's just a coincidence) is P0431 - Warm-up Catalyst Efficiency Below Threshold Bank 2. My question is, since I am only getting that one code, and most people report multiple codes at the same time in many of these forum posts, how can I tell whether the 02 is bad or whether the cat is actually failing? Does the 02 spacer usually alleviate the problem for this situation or will it just cover up that the cat might actually need replacing?
Thanks for the help, also - OP, were you able to fix your problem?
The code I'm getting pretty regularly, especially since it has gotten colder (maybe that's just a coincidence) is P0431 - Warm-up Catalyst Efficiency Below Threshold Bank 2. My question is, since I am only getting that one code, and most people report multiple codes at the same time in many of these forum posts, how can I tell whether the 02 is bad or whether the cat is actually failing? Does the 02 spacer usually alleviate the problem for this situation or will it just cover up that the cat might actually need replacing?
Thanks for the help, also - OP, were you able to fix your problem?
AudiWorld Super User
Joined: Aug 2004
Posts: 3,277
Likes: 2
From: Toronto
While I've never posted on here, I have prowled the forums for sometime now since my semi-recent Audi purchase... Also, I realize that my question has been asked many times before, and I've searched multiple forums and read at length regarding the O2/cat debate (as far as which is to blame for my particular code) but I couldn't find any specific info regarding whether a spacer would alleviate the problem or not.
The code I'm getting pretty regularly, especially since it has gotten colder (maybe that's just a coincidence) is P0431 - Warm-up Catalyst Efficiency Below Threshold Bank 2. My question is, since I am only getting that one code, and most people report multiple codes at the same time in many of these forum posts, how can I tell whether the 02 is bad or whether the cat is actually failing? Does the 02 spacer usually alleviate the problem for this situation or will it just cover up that the cat might actually need replacing?
Thanks for the help, also - OP, were you able to fix your problem?
The code I'm getting pretty regularly, especially since it has gotten colder (maybe that's just a coincidence) is P0431 - Warm-up Catalyst Efficiency Below Threshold Bank 2. My question is, since I am only getting that one code, and most people report multiple codes at the same time in many of these forum posts, how can I tell whether the 02 is bad or whether the cat is actually failing? Does the 02 spacer usually alleviate the problem for this situation or will it just cover up that the cat might actually need replacing?
Thanks for the help, also - OP, were you able to fix your problem?
AudiWorld Member
Joined: Dec 2013
Posts: 183
Likes: 0
Post-Cat 02
Thanks for the info, I'll give it a try. Two more quick questions if you or someone else can answer them.... 1)While I'm there, should I do the same to the passenger side? 2)If it fixes the code but my cat is actually on its last leg (140k miles) will it throw another code in the event that it needs a replacement?
AudiWorld Senior Member
Joined: Mar 2004
Posts: 911
Likes: 17
O2 spacer
With the spacer, you could gut your cat or use a test pipe, so you should never get a cat code. I've seen a couple of posts where people needed 2 spacers, but I think those may have been heavily modified cars.
I did both even though only my passenger side was throwing the code(same code as you're seeing).
I did both even though only my passenger side was throwing the code(same code as you're seeing).
Trending Topics
AudiWorld Super User
Joined: Dec 2003
Posts: 2,244
Likes: 3
From: Gardnerville, NV
AudiWorld Stories
Bringing Audi to Life for Audi Fans
Top 10 Most Expensive Audis Ever Sold on Bring-A-Trailer
Brett Foote
10 Audi Features & Options We Miss the Most!
Joe Kucinski
Audi Recreates Crazy-Looking Speed Record Breaker From 1935
Verdad Gallardo
Coachbuilder Recreates the 1995 Audi TTS Concept
Verdad Gallardo
Every Audi V10 Car Ranked!
Joe Kucinski
9 Audi Designs That Aged Like Fine Wine
Verdad Gallardo
2026 Audi Q5 Buyer's Guide (Every Model Explained)
Brett Foote
Ranking Every Current Audi 'S' Model From Worst to First!
Joe Kucinski
10 Best Audis That are FINALLY LEGAL to Import to the U.S.!
Joe Kucinski
AudiWorld Member
Joined: Dec 2013
Posts: 183
Likes: 0
Check out this link.
http://forums.quattroworld.com/a6/threads/4322.phtml
http://forums.quattroworld.com/a6/threads/4322.phtml
AudiWorld Super User
Joined: Oct 2006
Posts: 2,436
Likes: 95
From: In my Garage
i put on the universal bosch ones and slpiced them .. no issues .. you are right .. they clip the damn things to the top of the transmision and then lift the transmision into the car ... when i did mine i unscrewed from underneath , then i went up to and cut as far down the wire as i could from the factory connector as i didnt know how far the universal wires would reach .. then just ripped the wires out from under the car .. redid the sensors on my kitchen table and restrung it when i put it back .. all good so far .. not a job i would want to do in January in Canada though ... so glad i got it out of the way ..