A few weeks ago, my Phantom 2 crashed into a freshwater pond. The battery was thrown out upon impact. The drone spent about 30 seconds at most in the pond before I got it out, after which I immediately took it home. I opened it up and let it dry completely in the sun.

Fast forward to today, I recieved two new batteries (the old one was recovered, but non-functional), as well as an FPV module. I was under the assumption that such brief exposure to relatively benign water wouldn't damage the drone.

Whenever I turn the drone on, the two rear arms flash yellow slowly after the normal built in test indications. I'm running in Naza M mode. There is no mention of what this code means anywhere in the manual or internet. (This is what's so unbelievably frustrating about the situation) Additionally, the GPS module gets extremely hot, and the drone pulls about 12 watts constantly.

Of course, the motors won't start. There is no change in the lights when I attempt a CSC, despite the fact that all indications in the software are completely normal, I even did a full recalibration of the IMU. The only thing I can see is the reciever type is set to D bus, apparently this is a common problem with no obvious soution.

I'm 99% sure I'm gonna have to throw the drone in the bin, just wondering if anyone has had similar issues before.

Correction: The slow yellow flashing was in Phantom mode. In Naza M mode, the lights blink yellow about once every two seconds, and when I do the CSC, they flash twice before resuming the low blinking.
Edit: Alright, it looks like the issue is the GPS module. Unplugging it results in exactly the same response. It got so hot that just touching the circuit board burned me. Probably fried completely. God, I hope I can buy a replacement....

On my P2V and plus, slow flashing yellow in the rear means it's in ATTI.  

Two quick flashes in the rear every second or two means the control sticks are not centered.

Mark The Droner Posted at 2017-4-25 02:20
On my P2V and plus, slow flashing yellow in the rear means it's in ATTI.  

Two quick flashes in the rear every second or two means the control sticks are not centered.

I know what you're talking about but this is different.

When i first powered it on after the crash, i was getting faulty controller calibration errors. Then it switched to GPS/compass errors. Now, it just does the yellow flashing with no GPS status indications, regardless of flight mode.

My guess is this:

The GPS module sustained some sort of water damage that caused a soft short somewhere. This made the module dissipate ungodly amounts of heat until it destroyed itself internally. Theres no change between having it plugged or unplugged.

I just ordered a new Naza M 2 GPS module, fingers crossed.

Update: resolved! The GPS AND main board were faulty. Replaced both and it flies with no apparent issues.