PP signal is proximity pin, also known as plug present. It need to get EV information when socket connected with plug. From J1772 description, it operates with resistanses and button-switch, which are built-in to connector and provide PP-to-EARTH voltage drop for EV side. For a simple, there should be installed two serial connected resistors 150 Ohm and than 330 Ohm from PP to EARTH pin. 330 Ohm should be shunted with switch on connector. You can try that, and it will works. If you left it open, it will not.