I see that this thread is over two years old now, but I'm having the exact same issues as OP and yet, non of the solutions worked for me. I have reinstalled the vehicles several times, as well as ELS, LSPDFR and RageHookV. So far, my inclination is that ELS doesn't recognise the vehicle is ELS compatible, even though it is. CTRL P just pauses the came, Scr Lk just takes a screenshot, J doesn't cycle anything at all. I can press E to activate sirens and flashing tail lights (Break lights only), and J does deactivate the sirens, but that is all I have.
Can anyone here help me? I'm hoping so. I thought trying here would be best first before starting a new threat on here or Reddit