Broken links within PDFs will prevent people from discovering and using your content. In addition, Google treats links in PDFs the same as links within Web pages. They pass PageRank and other indexing signals, and will be followed when crawled.
Checkpoints - PDFs - Documents with broken links
This checkpoint will scan your PDF files and search for broken links. If a broken link is found it will be flagged. Broken links are identified based on the link's HTTP response codes.