Problem to start Nissan Sentra B14

Good morning, for a few days it has been complicated to light the car, turn the key and give in -interplay and accessories, for starting, it does not start.

I have noticed that in cold weather, or when it has been very off it costs me more to turn it on.
A mechanic reviewed it and told me that the llavin and the pill are wrong. But I want to know other opinions

thanks

Dear friend, the same problem was presented to me, and after a lot of attempts and throwing money I recommend you better that you buy the entire new set, I buy the pill I replace it hard as a month and then the same problem, I have tried the following and in the end I have come to the conclusion that it is better to buy the entire new set, send the key again, 10 thousand colones Buy a second llavin with everything and hard a month and a half and again I am in the same problem so I recommend that you invest in something new and do not throw the money as I did !! That you are well