My '99 accord with 195k overheated. Replaced the thermostat and heater hoses. Engine is running fine except for the P0117 code which could be the IAT sensor. Should I bother to replace the sensor or can I reset the check engine light - if that is possible. If the check engine light can be reset, please share the procedure.

 

Go to any auto parts store and request that they reset it. Some do this for free. Brett Pindell

 

...you could also just pull fuse #13 (7.5A) from the passenger side under-dash fuse box for 10 sec with the key in the off position. RESET!!

P0117 is thrown for low voltage on the ECT [engine coolant temp] circuit, (not the IAT [intake air temp]). seems related to the recent work done to the car.
you can check it with a multi-meter at operating temp (after the radiator fan has cycled at least once) you should see 0.4~0.7V. if in range reset the ECU as described above and continue driving. if it's not in range double check the thermostat and the rest of the work done on the cooling system. if all is good replace the sensor.

edit: oh, and don't forget the simple things like a loose or disconnected sensor wire...