When i open the door by putting the code on the panel ffrom outside it does not open but it closes with the same code .
Your battery may be getting weak. Replace it and try.
Even after changing the battery its still the same old ,Infact there are two sensors, the light on one of them is low as compared to the other one .
It sounds like the signal from the keypad has gotten weak. Do your regular car remotes work ok? If you are referring to the door sensors as long as the door closes they are ok.