Micromax Q427+ - Proximity sensor is not working; Proximity Sensor Troubleshooting

Q427+ L3 Service Manual
 Check the CPU work normally or not, Re-Solder CPU or change it
23.GPS cannot locate and open:
Solution:
 Check BT 11 to 30 S if these are working fine。
 Flash the handset with latest SW
 Check the GPS antenna normally or not, then Re-Solder or change it.
Power IC
Sensor