Well, the camera is correct for your model. That's good. PWM signal is essentially a "square wave" DC signal. It is pulsed on/off at high frequency. The percentage of time the signal is on, multiplied by the source (battery) voltage, produces an effective lower voltage. However, that's not the whole story. The on/off pattern does not have to be constant. It can be pulsed on and off in such a way as to create a "code" within the signal. I don't know what the effective voltage would be, probably around 3 or 4 volts, but without knowing the correct code pattern, and without having an oscilloscope to check it, just finding the correct voltage on the pins would not really tell you the whole story. Have you tried to contact Yuneec customer service? The customer service reps usually can't tell you much more than "send it in and we'll look at it", but sometimes if you ask to speak to a service rep you can get some useful info. I've found them to be easy to talk to, and pretty good at the higher level stuff. They can't talk to me about the deeper stuff, because I wouldn't understand it. Maybe they can/will help.
By the way, be cautious about checking the voltage, After I managed to short the contacts and fry my control board, I made an adapter to plug into the drone for the sake of safety.