At my school we have a PLTW Engineering Academy. These classes are listed a-g but I have a gut feeling that they not too common and would like to write about it in the “Activities & awards” section in other coursework. However, for listing other coursework, it says, “These are courses other than those required for UC admission (courses that do not fit in UC’s “a-g” subject areas)”.
If the course is listed in the UCOP a-g course list for your High School, you need to list them under the appropriate a-g course category on the UC application.
PLTW courses are not unknown to UC admissions but you can always use one of the personal insight questions to further elaborate on the PLTW academy if you like.
Look for your school here: https://hs-articulation.ucop.edu/agcourselist and see if all of your PTLW courses are listed in either the science or elective sections. If so, list them with your coursework and not in the activities section. Did you participate in any extracurricular activities related to the PTLW courses (ex. robotics, solar boat, VEX)? If so, you can expand on those in the Activities section.