I have 2018 f-350 6.7 Powerstroke. The CEL just activated, code generated P20C2. I read up a bit about the issues that can trip this code and resulting severity. I scheduled a service to get it addressed but that is a month out.

My understanding is that the reductant heater is not activated until the reductant temperature sensor detects the DEF approaching a freezing temperature. So until the reductant temperature threashold is reached, the heater is not activated. The heater is not used until needed. Is this a valid understanding? Also, I believe there are three reductant heaters (tank,pressure,pump) on the 2018 f-350.

The CEL tripped at startup, after a brief shutdown (engine was at normal operating temperature at shutdown). When I scanned for the fault I got P20C2; no other DTCs present. The ambient temperature was about 70f; there is no risk of any DEF freeze out.

Also, the article I read specific to this code (P20C2) indicates if it trips during warm weather suspect a PCM programming error. .( https://www.obd-codes.com/p20c2 ). My vehicle is 100% stock.

I am just trying to get a better understanding of the issue and learn what other owners have experienced.

Best wishes to all.

 

You may have already read this> https://www.obd-codes.com/p20c2

I think if it were me, I would clear the code and see if it comes back, because as you have already said, the heater shouldn't be on at the current ambient outside air temps.

 

Check your connector to the DEF heater, make sure it's seated all the way.

 

I thought about that as an option. Do you know if this fault will self correct after X number of no fault driving cycles?

 

I removed the plastic dirt cover (collector) on the bottom of the DEF tank. The connector (two wire) looked good, but I gave it a mild tug just to be sure. And....the CEL cleared during startup. So I don't know if this was the fix or if I had enough run cycles to clear the CEL.

 

Wait and see...