mate it doesn't i got solution for proximity sensor issue in Micromax a73.
for this you need to root your phone first.
2.After rooting go for es file manager.
3. In this file manager select root exploration enable.
4.Than select this path device/sys/devices/platform/alps/driver.
5.There you find 2file named thdlow & thdhigh .
6. Open those files with text editor and u see that both have same value=300.
7. So u just need to change these value as write 1023in thdhigh and in thdlow 599 and save it. finally open properties of both file and change permission to read only. Thats all. Now close it and enjoy calls with light on.
thanks for reading.help me at all I tried g sensor but doesn't even give a chance to calibrtate and ps calibration also doesn't seem to b working