boonies

Second set of 02 sensors in about 30 days. The first set were 1/2 the cost (eBay), but failed after about 1,000 miles and set a lot of codes on both banks. The seller did fully refund the cost...

Following the advice of others on the site I purchased Bosch OEM quality replacements. Interesting difference in quality... not only did Bosch match the look of the OEM sensors exactly, but they came with anti-seize compound on the threads.

This job was a breeze! Having already experienced the replacement just a few days ago, I completed the job in two hours (both sides). I had the good fortune of having access to a lift so it does make the job a little easier.

Once again, thanks for the advice on replacement sensors and on the procedure which I found on Paul W's D2 A8/A8L/S8 FAQ Digest

Sleeper8

I'll be doing the same on the A-car shortly, but it will be easy in the car's current configuration.

boonies

Drivers side is easy using an 02 sensor wrench (off-set style). Passenger side is a challange. I used a 7/8 open-end wrench (or 22mm). The attached link from Paul W's FAQ (original post by gondar) describes the job perfectly!<ul><li><a href="https://forums.audiworld.com/a8/msgs/164940.phtml">https://forums.audiworld.com/a8/msgs/164940.phtml</a</li></ul>

PaulW

I know I am beating a dead horse....but purchasing high quality parts really seems to lower the load when doing repairs. I've learned the hard way. Glad it worked out for you.

boonies

The cheap 02 sensors were setting:
17521p0113 bank 1 sensor 1 resistance too high
17978 p01570 engine ECU blocked
17831 p1423 secondary air bank 1 flow too low
17819 p1411 secondary air bank 2 flow too low
17539 Bank 2 sensor 1 resistance too high
16518 P0134 Bank 1, sensor, 1 no activity

so far (about 65 miles) no check engine light!