So, my F450 threw a P20B9 code again last November and I was hesitant to replace the Reductant Heater "A" since it's been replaced twice in the last six months, first by Ford as a recall and second by me 6 months later if that while I was down in TX visiting family 3 months ago. So, I've bought. Another Reductant heater, the Exhaust fluid pump, a new exhaust fluid pump wiring harness, the injector feed line and the Temperature sensor probe at the end of the line. I'm waiting a couple more days for the Polar Vortex madness to end before I go out and drop the thing again. I also replaced the Reductant Heater "A" fuse and relay. I'm replacing the two fuses and relay to the PCM since it says the PCM has detected zero voltage to the Reductant Heater "A". I've read it could be the glow plug module and on and on who knows. Why Ford built a heavy-duty truck with a plastic tank under the bed with DEF fluid in it that freezes every night in the winter is a mystery to me. My original thoughts were that the heater came on at night while the truck is parked but I don't think that's true either. Also, if you have too much fluid in the tank it'll break when the exhaust fluid freezes. Well, I don't believe I've got that problem yet, but it would be nice to have a gauge how full it is just not how empty it is, but that would be too easy. :-) Don't get me wrong, I love my F450, just not the emissions part. Also, the EGR cooler has been replaced twice, last time by Ford under a recall. I bought one to replace myself but when I found out Ford was replacing them, I kept it anyway because I know it's going to happen again. Well thanks for letting me vent a little bit. So, if anyone knows anything I may be missing it would be greatly appreciated! Thanks!