No problem as such and you can definitely appear flr improvement exam and Jee Main 2019 how ever you must have passed PCM subjects. 

Also in future there might b eproblem as year gap in interview roubds and can be questioned. 

So you nees to prepare well for that and answer any suitable valid reason. 

Hello Ayush,

No, there will be no problems associated with you appearing again in your board examination. You would be required to have at least 75% marks in your Class 12th Board overall among 5 subjects.

For more information on the eligibility criteria of JEE Main 2019, kindly go through the following article: https://engineering.careers360.com/articles/jee-main-eligibility-criteria

Please feel free to comment below for further assistance.

All the best!!