So  I crashed my Phantom 4 today and I'm trying to figure out what exactly  is wrong that's keeping me from flying it again.  I'm good with  electronics and am pretty sure I could replace motors etc myself but I  don't know where to start, or even if the motors are what's wrong.

During  the crash my battery fell out and three propellers broke.  The legs  took the brunt of the landing and there are some minor cracks on the  main body where they attach.  I lost one of the leg covers (where you  access the motor connection), two of them had fallen off but I found one  nearby.

Trying to fly the drone I  am getting two yellow flashing lights on the back.  All of the  propellers do their initial engagement but it looks like the front two  and maybe the back right prop don't move as much during that.

All  of the apps I use to fly (DJI GO, Litchi etc) report zero battery, even  though the battery is connected and full.  Even my spare batteries that  weren't in the crash report as empty.  DJI GO says "connected" like  normal but Litchi says "disconnected".

I'm  still able to connect to the drone and move the camera around, I can  see the video feed from the drone and take pictures.  Trying to takeoff  fails.  I get an error message in the app and the drone does nothing.   Everything with the camera and gimbal seems fine.

Since  the battery fell out in the crash is it possible that something in the  drone needs to be reset?  It seems strange that it would report zero  power while showing me the camera feed.

Hello there DTDrone. I am sorry to read and to know what happened to your DJI Phantom 4 and thank you for reaching out. Since there was a crash that happened before. It would be best to contact our DJI support team at https://www.dji.com/support for us to be able to assess the said DJI Drone for damages. We will do there best to help and give out the best resolution for this issue.  If the said DJI drone is still under the warranty period and it is evaluated as a non-pilot error, the warranty service will be provided. Again I am sorry for this trouble and thank you.

Sounds like ya need to get it serviced, only thing i can think of is to do a ECS calibration, i think that abbreviation is totally incorrect, I'm sure you will know what i mean but that wont fix the power issue though, I'm sure it wont, ya need to send it in best off doing that anyway after such a crash....