What kind do I replace this with?
This is not a diode, but a tantalum capacitor. When powered up, there should be about 3.3 volts across it.
To build off of what I replied to one of your earlier posts, try removing the capacitor and powering the device up. Decoupling capacitors might not be required for it to function. Replace it with any moderate capacitance cap if it still doesn't work.
It might be a failed component causing a short. I've noticed that switching regulators can make a squeaking noise when they are being overloaded, causing the switching frequency to drop to audible ranges, and becoming sound through piezoelectric effects of capacitors.