It is difficult to give a definitive answer on whether you can join a BE/BTech (Bachelor of Engineering/Technology) program through open intermediate with a diploma and ongoing open intermediate studies.

I am assuming you meant BE/BTech (Bachelor of Engineering/Technology). It is a common engineering undergraduate degree in India.
Eligibility criteria for BE/BTech programs vary depending on the university. Some might accept students with a diploma, while others might require a full 10+2 education (higher secondary education).

I hope it helps!