Help on a few issues

1- When I make a left and right in the steering wheel, click sounds like clicks. What could be the reason for this?

2-How do I get rid of the following antipollution fault error? I made gas adjustments many times, no, no.

3-After changing the last gearbox chock, the car started to vibrate and a buzzing sound similar to the gearbox sound started to emerge. Does this have anything to do with changing wedges? Because there was no such voice before changing.

Thanks.