205c code

Check engine light just came on my 2012 6.7 with 150k miles. Pulled the code and it was 205c, DEF tank temperature sensor low voltage, correct?

When I purchased it (fall 2022, 108k) there was a service bulletin for the DEF tank heater assembly so it sat at the dealership for a couple months getting that repiar.

My question is two fold, is this a dealership fix? Seems related but almost 4 years after the warranty work, could it be a separate issue? Secondly, it is the middle of summer and my understanding is DEF only needs the heater to keep from freezing, is this a repair that can wait? I can afford to park it at the stealer for a few months in the middle of winter but not during my busy season. But also I tow frequently and can't afford limp mode either...can this sensor voltage issue really cause limp mode?