Hello aspirant, the answer for your question is yes and no. Admission criteria through lateral entry into B. Tech courses after diploma is highly dependent on the university in which you want to apply . There are some universities that ask you to give a test and accordingly you can choose a branch other than the one in diploma. There are also many colleges that do not allow change of branch after diploma. So you need to go to the website of the university in which you want to apply and check if they allow branch change from CSE to mechanical after admission through diploma or not.