Trouble code p1634 for bmw740il?

Question

2000bmw740il was in failsafe program. I scanned using obd2 .a single code came up p1634. Is that an o2 scenser or something else . I erased the code it's now out of failsafe program, however the check engine light came back on. I need to smog this vehicle asap to get 2018 tags