Finding a short on my iPhone 5s

If I find a short why can’t I just hook up the DCPS to the battery terminal and use freeze spray?

·         You can but what do you think will heat up the shorted IC or cap or the charging mosfet?

What is the importance of “injecting“current directly into a cap into the line?

·         For VCC main it bypasses the charging mosfet. For other lines it’s the only way to inject voltage into the line.

If there is a short on PP5V0USB can I find the short by injecting into VCC MAIN since VCC MAIN supplies those rails too?

·         No VCC main supplies the power management chip. The power management chip supplies all the other rails.

On the ammeter the phone only pulls 0.12 amps, what does this tell me about the possible issue with the phone?

·         It tells you the phone is not charging. Do not try and diagnose a phone with a usb ammeter.