get p20e8 code

Question

changed heater and pump and line still get the same code, I think it is a pcm problem

Answer 1

P20E8 Reductant pressure too low

The reductant has a pressure sensor, provided it is correctly giving the pressure. The pump itself they are know for its internal leak setting P20E8 .You may even have a faulty pump. what Ford 2011 does not set a P20E8.  The PCM there a Recall for it. and especially during exhaust regeneration. Let the dealer reprogram PCM it according to the Recall for it. You may need to get the warranty for the pump and do it again