A6 / S6 (C5 Platform) Discussion Discussion forum for the C5 Audi A6 and S6 produced from 1998-2004

can the ECM be programmed with VCDS to ignore O2 sensor 2

Thread Tools
 
Search this Thread
 
Old Apr 2, 2018 | 06:03 PM
  #1  
meternerd's Avatar
Thread Starter
AudiWorld Member
 
Joined: Jul 2004
Posts: 269
Likes: 3
Default can the ECM be programmed with VCDS to ignore O2 sensor 2

Now that I'm out of Kalifornia and no longer need to pass smog, can I disable the Check Engine light for an inefficient cat (sensor 2, bank 1) using VCDS? I'm not sure if it's the sensor or the Cat, but the sensor looks to be impossible to remove and it may not even be the problem. 2001 A6 2.7T Quattro.
Reply
Old Apr 3, 2018 | 04:43 AM
  #2  
johnkk's Avatar
AudiWorld Senior Member
 
Joined: Mar 2004
Posts: 911
Likes: 17
Default

VCDS cannot code out the sensor. Other software can like nefmoto, vag commander may be able to. Put an extender on the sensor to make the code go away. You can make them by drilling out a sparkplug extender or buy one. Easy diy

If you heat up the sensor bung with a propane torch, it will come out easily.
Reply
Old Apr 3, 2018 | 07:51 AM
  #3  
dwengi's Avatar
AudiWorld Senior Member
20 Year Member
Liked
 
Joined: Dec 2004
Posts: 603
Likes: 4
Default

Some ECUs can be re-flashed by the dealer to raise the cat inefficiency threshold - Mine could not so I used plug extenders which solved the problem.
Reply
Old Apr 3, 2018 | 02:58 PM
  #4  
clancy's Avatar
AudiWorld Senior Member
20 Year Member
 
Joined: Jan 2004
Posts: 1,417
Likes: 28
From: Ocean Isle Beach NC
Default

I have used the extenders with success on a 2001 A6 2.7 and a 2000 A6 2.7
Reply
Old Apr 4, 2018 | 12:13 PM
  #5  
meternerd's Avatar
Thread Starter
AudiWorld Member
 
Joined: Jul 2004
Posts: 269
Likes: 3
Default

Thanks for the replies.....I managed to clear the Code for a bad heater on the sensor using a 12v light bulb across the terminals, but the one for inefficient Cat came back. The bank 1 sensor 2 is mounted on top of the passenger side front "muffler" and there's no way to get an O2 socket on. I tried an open end wrench, but hard to get a good "bite". I hesitate to buy a replacement until I can break the bad one loose, so maybe the torch, vise grips and a beer or two will help. The extender sounds like a good solution IF I can get it off and pull enough wire to hook up a replacement. I was looking at the Bosch universal with the connector, since I read that the routing of the factory wire leaves almost no way to get the wire and old connector out without dropping the tranny. True? For now, I just have a small piece of black tape over the Check Engine light so it doesn't bug me....type A that I am, I hate stuff that doesn't work!

Last edited by meternerd; Apr 4, 2018 at 12:16 PM.
Reply
Old Apr 4, 2018 | 01:02 PM
  #6  
clancy's Avatar
AudiWorld Senior Member
20 Year Member
 
Joined: Jan 2004
Posts: 1,417
Likes: 28
From: Ocean Isle Beach NC
Default

Those O2 sensors on the back cat are a bugger. Then there is the wire routing to deal with. Neither is fun. Lots written about both. I'd first use PB blaster or Kroil or similar for a day or so. Best wishes.
Reply
Old Apr 4, 2018 | 03:50 PM
  #7  
dwengi's Avatar
AudiWorld Senior Member
20 Year Member
Liked
 
Joined: Dec 2004
Posts: 603
Likes: 4
Default

The wires appear to be zip tied to the top of the trans/bell housing and as near as I can tell are impossible to access.

To get the stuck sensor out - maybe cut the wire and use a box end wrench with a cheater bar? You can always reconnect the wires if it doesn't work.
Reply
Old Apr 7, 2018 | 09:36 AM
  #8  
meternerd's Avatar
Thread Starter
AudiWorld Member
 
Joined: Jul 2004
Posts: 269
Likes: 3
Default I'll try getting it out,but....

If I can't get it out, I'm going to try wiring in a "low pass filter" as suggested in one video. If it does break loose, I'll see if I can get any wire slack. As it looks right now, the wire is tight and no slack is available at either end, so if I cut it, there's no wire long enough to splice in a new one. Does anyone but me wish evil on the engineers who decided to make everything so difficult?

Last edited by meternerd; Apr 7, 2018 at 09:38 AM.
Reply
AudiWorld Stories

Bringing Audi to Life for Audi Fans

story-0

New Audi A6 Allroad Is The Market's Coolest Wagon: 9 Things to Know

 Pouria Savadkouei
story-1

10 Strangest Audi Designs That Actually Made Production

 Joe Kucinski
story-2

2027 Audi Q7 and SQ7: Audi Upgraded EVERYTHING!

 Michael S. Palmer
story-3

Audi Unveils Absurdly Cool New Supercar: 10 Things You Need to Know!

 Verdad Gallardo
story-4

The Highs & Lows of Every Audi C-Class Generation

 Joe Kucinski
story-5

Top 10 Most Expensive Audis Ever Sold on Bring-A-Trailer

 Brett Foote
story-6

10 Audi Features & Options We Miss the Most!

 Joe Kucinski
story-7

Audi Recreates Crazy-Looking Speed Record Breaker From 1935

 Verdad Gallardo
story-8

Coachbuilder Recreates the 1995 Audi TTS Concept

 Verdad Gallardo
story-9

Every Audi V10 Car Ranked!

 Joe Kucinski
Old Apr 7, 2018 | 10:08 AM
  #9  
clancy's Avatar
AudiWorld Senior Member
20 Year Member
 
Joined: Jan 2004
Posts: 1,417
Likes: 28
From: Ocean Isle Beach NC
Default

I would count on somehow getting them out. It took me a few days of solvent soaking and grunting before mine came out. Obviously the proper wrench is key. No crescent wrenches. If you cut the wires with the idea of reconnecting the original if it cannot be removed then plan on simply adding length to the wires. Normally I would just solder on extensions but Bosch told me to not solder the wires. Said it did something to the sensors???? Never understood but accepted their advice as they should know.

Originally I labored on not being able to snake the wires of the new sensors to the original locations. Then just quit fretting and routed them where I thought they needed to be. That was a few years ago and have not had any issues.

I do not believe Audi engineers care a whit about how their method of assembly and attachments affect future service tech repair. They and the product managers only care about the lowest cost assembly for the performance they design. Difficulty later means more labor dollars for the tech.
Reply
Old Apr 7, 2018 | 10:46 AM
  #10  
meternerd's Avatar
Thread Starter
AudiWorld Member
 
Joined: Jul 2004
Posts: 269
Likes: 3
Default Well RATS...

I took the VCDS out and connected to engine measuring block 030, and it showed no activity or heater on the Bank 1 Sensor 2, so looks like the low pass filter won't work. Looks like it could be a broken cable, but no way to get to it. I guess, when the weather warms up, I'll give it a try getting the sensor out. If I can, I'll just install the replacement (with the extender) and run new wire all the way to the connector. As far as solder, it's because the wires are some kind of alloy, and solder won't stick, but a butt splice will work fine and copper wire to the connector will also work fine. For now, the "black tape fix" will have to be good enough. I'll just have to keep checking codes to see if any new ones have shown up. Thanks again for all of the suggestions.
Reply



All times are GMT -8. The time now is 01:21 PM.

story-0
New Audi A6 Allroad Is The Market's Coolest Wagon: 9 Things to Know

Slideshow: Audi's latest A6 Allroad gets RS-style fenders, real off-road hardware, and enough personality to stand out in a market obsessed with crossovers.

By Pouria Savadkouei | 2026-06-16 17:31:52


VIEW MORE
story-1
10 Strangest Audi Designs That Actually Made Production

Slideshow: 10 strangest Audi designs that actually made production

By Joe Kucinski | 2026-06-10 16:32:29


VIEW MORE
story-2
2027 Audi Q7 and SQ7: Audi Upgraded EVERYTHING!

Slideshow: Everything you need to know about the 2027 Audi Q7 and SQ7

By Michael S. Palmer | 2026-06-09 06:02:56


VIEW MORE
story-3
Audi Unveils Absurdly Cool New Supercar: 10 Things You Need to Know!

Slideshow: Limited to just 499 units, the 987-horsepower halo car signals a new chapter for Audi performance.

By Verdad Gallardo | 2026-06-04 17:37:15


VIEW MORE
story-4
The Highs & Lows of Every Audi C-Class Generation

Slideshow: The highs and lows of every Audi C-Class generation.

By Joe Kucinski | 2026-05-27 16:05:50


VIEW MORE
story-5
Top 10 Most Expensive Audis Ever Sold on Bring-A-Trailer

People were more than happy to shell out big bucks for these cars.

By Brett Foote | 2026-05-27 15:32:23


VIEW MORE
story-6
10 Audi Features & Options We Miss the Most!

Slideshow: 10 Audi features and options we miss the most.

By Joe Kucinski | 2026-05-12 19:33:47


VIEW MORE
story-7
Audi Recreates Crazy-Looking Speed Record Breaker From 1935

Slideshow: Audi has recreated one of the wildest machines of the pre-war speed-record era, reviving a streamlined V16 racer that originally exceeded 200 mph in 1935.

By Verdad Gallardo | 2026-05-11 09:49:34


VIEW MORE
story-8
Coachbuilder Recreates the 1995 Audi TTS Concept

Slideshow: A Dutch coachbuilder has reimagined the original Audi TT by finishing what the 1995 concept only hinted at.

By Verdad Gallardo | 2026-05-05 15:17:58


VIEW MORE
story-9
Every Audi V10 Car Ranked!

Slideshow: Ranking every Audi V10 road car

By Joe Kucinski | 2026-04-29 16:11:56


VIEW MORE