meternerd

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.

johnkk

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.

dwengi

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.

clancy

meternerd

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!

clancy

dwengi

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.

meternerd

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?

clancy

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.

meternerd

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.