Service Engine Light On problems of the 2016 Ford F-250

Service engine light came on twice while vehicle was under warranty. Dealer serviced both times and was unable to rectify or understand the problem. They only cleared the fault codes. The code identified was for the reductant heater pump - low voltage. The same code just came back on for the 3rd time - this time identified by a diesel performance shop - with advice to replace the reductant pump. Previous make and model superduty trucks have had recalls for the same thing. This is an obvious issue, not sure why Ford service shops could not rectify. Truck is now out of warranty and I am forced to pay out of pocket. Unacceptable service and care! -cold weather each time -engine light comes on - same code each time -reduced speed and sluggish performance -code cleared - truck performs normal -obvious that the reductant heat pump is not doing what it is designed to do.