First, you can download the PMML specification here and use any online tool, like this, to validate your PMML file.
You can find the list of PMML producers and consumers in this link. You may use KNIME, an open source drag & drop application which supports Python, R, and Java, to import your model and check if it is recognized by KNIME.
You may also use ADAPA to further examine your PMML file to see if it contains a valid model. ADAPA is available on AWS (Amazon Web Services) as SaaS but you can use it for free for 14 days, I believe. It's the most comprehensive PMML validator, convertor, and executer.