Toyota Etios & Liva has immobilizer in its cars which works as theft deterrent. It stores its codes in special 8 leg EEPROM IC 93C66. We got a special case where one connection on circuit to IC was missing.
On close inspection, we found that this connection sends the signal to processor via the path shown below.
We connected the wire from processor using solder iron which later is connected to EEPROM IC. This arrangement resulted in successful starting of the car.