I use a TIP32C transistor to switch the power line of SIM800L module, but unfortunatelly this method not working. The module is power on, but blinking every sec instead of every 3 sec. If i connect the power pin of the module to vcc then works fine. The GPIO is 3,3V and the VCC is 4V.
try R1 = 680R and/or search for High Side Switch to get the base closer to Vcc. You are really on the boundary of getting the base close enough to Vcc to switch it fully off.
This SIM800 has anyway a shutdown pin PWRKEY (or similar).
I suspect it is because the voltage to the SIM800L is to low. VCE(sat) of your transistor is 1.2V. 4V - 1.2V = 2.8V. You could use a MOSFET with much better results. If you can do low side switching, by using a logic level UIS rated MOSFET. A P-Channel MOSFET would work but it is a little more involved in the drive circuit. To use the N-Channel MOSFET connect Source to ground, Drain to the SIM800L and the gate to the GPIO. Use your existing 10K to pull down the GPIO to ground. That is to guarantee it is off during reset. I would normally use something in the 25 ohm range between the gate and GPIO but it should work just fine without it.
Can i connect direct the gpio pin to the Logic level MOSFET's Gate If the SIM800L module consume 2 amps for 500 microseconds? After consume only 200 mA.
Yes, the MOSFET is a voltage driven device, a transistor is a current driven device. I would suggest also connecting the GPIO pin to ground with a 10K resistor to keep it off during reset and startup. You might want to add only the resistor first and test it, if it fails boot you need to use a different GPIO. Most microprocessors tristate there outputs during that period. If it mounted on a board such as the ESP devices they may have a resistor to control the pin voltage during boot so it can select the proper mode.
Low side switching of a module , say by an N channel mosfet, introduces a risk of phantom powering through one of the connected signal wires which could be minimised by forcing their pins into high impedance mode.