the P1000 means that you have either had the battery disconnected recently or your PCM has been reflashed recently.
the P0161 and P0141 mean that the post cat O2 sensors are not reading correctly. you either have high flow cats, or have no cats. if that is the case you need O2 sensor simulators, or else get the rear O2 sensor inputs turned off via a PCM reflash or a dyno tune.
however, if you do have cats, i would look at a wiring harness issue. its rare for both rear O2s to go south at the same time. if it was the upstream sensors i would tell you to clean out your MAF sensor, however this is the post cat ones.
I 'circuit fault' code denotes that there is an actual electrical connection failure in the sensor. Theres a different set of codes for properly working sensors detecting no cats/bad cats.
Either the wires have been torn, melted, somehow mangled or faulty MIL eliminators (or a poor patch job) are installed.
The P1000 code will remain until all OBDII sensors complete their startup self-test, rear O2 sensors included.
Oh and BTW, this will not hinder the cars performance at all. Its just letting you know something is broken and you won't pass an emissions test.