Getting a "bad connection to #2 bank pre-cat oxygen sensor" code

[Manolito]

2004 325iT

I have forgotten the code, but its definition from the Peake tool book is as shown above.
It comes up every couple of weeks or so.

I cleaned and tightened the connector contacts. No change.
I swapped the two pre-cat oxygen sensors around. No change, still complains about #2 bank sensor, so the problem is in the car, not the sensor.

I was thinking that perhaps I had damaged the wiring harness while doing other work. All that I can see of it looks fine though.

Then I happened to mention it to a friend in Tucson who drives a Z4. He is getting the same code! #2 bank pre-cat sensor wire.

I always read and reset mine as soon as it happens. He says that his CEL goes out after a day or two.

Perhaps this is a common problem?

[Manolito]

Turns out this used to be a common problem. There were six software updates for the e46 in 2004. Each time the programmers fixed one problem, they broke something else. Apparently my car does not have the final code version, which was released in early 2005. The check engine code I am getting appears in a factory service bulletin, with the resolution being to reflash the computer with later software.

Seems odd that my car went 150k miles with the original oxygen sensors with no problem, and then when I put in new Bosch sensors, the problem flared up.