The U1000 error is unfortunately common and it typically means a communication issue on the CAN bus.
Since your auto braking is affected, it points to one of the control modules not communicating correctly.
It could be anything from a loose connection or corroded wire to a failing sensor or even the ABS module itself.
To diagnose it, you'll need to check the wiring harnesses to and from the ABS module and other related sensors for any obvious damage or corrosion.
Sometimes, simply disconnecting and reconnecting the battery can clear a temporary glitch.
If that doesn't work, a scan tool that can read Nissan-specific codes would be your next step to pinpoint which module isn't communicating. You should be able to do a basic scan at any auto parts stores for free!
