The way the Brickboard works, if you respond to anothers post, that person will get an email with your response. Posting to yourself just notifies you and that is not what you want.
You can also edit a post in the first few hours. This keeps down the number of posts that people read every day.
The search box on the AWD index page is very good. Just put in key words. The Brickboard will search "labels" which are in the box just below the verbage area of a post. Just keep it meaningful, like 153 or O2 sensor.

In regards to the A-2 1-5-3, sometimes it can just be cleaned of the carbon and it will work again. The sensor is a bit stubborn to remove from the rear of the cat converter and most mechanics will just replace it with a Bosh sensor. These sensors are not cheap, but they typically last a long time - over 150K miles.
If the signal is missing, it might just be the electrical plug that got dirty. You won't know until you get safety goggles and get under the car and look. But NEVER get under a car with the jack that is supplied with the car, that is meant to change a tire and will fail if the car is rocked even slightly. Your head and chest requires more than 6 inches of clearance and a falling chassis will get down to 3-4 inches. Ouch?

Klaus
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I still miss my 164 and my 854T. Just driving a V70R :)