Car wont start after a chilly night

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Hi everyone I recently started having an issue with my 2011 ford fusion se 2.5L. I have had this car for over 3 years and never really had any issue until now. Car wont start if it was left out in cold even for couple hours. I do have a block heater and i leave it plugged at night and it starts with first crank in the morning. I cant plug it in while i am at work so it becomes a real pain to start it. I never really had to use the block heater in the past winter when it also touched -35 degrees at night. For the past couple weeks i've been facing this issue. Here are some more details Oil change is due (i dont think that should be an issue). Battery was installed last year. Coolant level is good but never had it flushed (195000km) Car has a code P0605 Has anyone had this issue?