Hi Mohsin,
Just to give you confidence the conventional automatic transmissions (Non-ECT) do not have a lock up mechanism. So driving a car with a malfunctioning lock would not damage the transmission nor the ATF would get overheated. All the damage it can do is increase your fuel consumption a couple of Km per litre while driving on highways.
Second, as you are based in DGK you can carry out the initial diagnosis and repair on your own by following these simple steps.
1. Visually check the wire harness for any signs of damage, starting from the transmission and all the way to the ECM installed in the passenger compartment. If any damage is found get it repaired. Try out the car and see if the problem is resolved. If not move on to 2.
2. Raise your car on a car lift (Not on jacks). Remove left side engine undercover and pull out all wiring connectors on the transmission. Make sure to press the locks on the connectors otherwise they may get damage and will always give you trouble. Visually check both male and female terminals for rust or other deposits. Thoroughly clean both sides using a good electrical contact cleaner. Reinstall connectors, undercover and test again after lowering the car. If problem still remains proceed to 3.
3. Prepare to take your car to a big city dealership but before moving speak to them on phone and make out a judgement whether they are capable of working on ECT. Ask them if they have any technicians trained to repair ECT.
Good Luck
