What are the odds of being promoted when your Engineering Manager recommends you for promotion?

Hi. I work for a company in a department that was previously a nonprofit that was acquired. This year, my manager will recommend me for a promotion from Software Engineer to Senior Engineer. There is a strong case captured in my end of year assessment. I previously worked in education and in nonprofits, so I do not have a sense of what this sort of corporate HR promotion process is like. Could someone who has been hiring a while or worked in HR perhaps give me a sense of things beyond the engineering team? Are most of the promotions that engineering managers request declined or approved? What are the common reasons? Does it hurt or help to have prior year recommendations? And what should I watch out for as an engineer in terms of trusting a company to promote me when I am working at higher level of contribution than my title?