to start from the beginning, we took our 2015 into the dealer service for a P20BA code. They confirmed that it was the reductant heater needing replaced, and that our trucks VIN was 3 months past the cutoff for the extended warranty coverage... also that our independent coverage did not cover emissions. We took it home, watched all the videos, and replaced the heater ourselves easy peasy. First drive after replacing the heater, we got a P20E8 code, reductant pressure too low. Ordered the dorman diesel reductant pump, replaced it, also easy peasy. First drive after replacing the pump, we again threw another code... this time P20E9, reductant pressure too high. Downloaded Forscan and ordered the usb for it, and did deeper diagnosis... and found that there was high pressure at one sensor (sensor 1, don't know which of the 2 that is... pump side or line side) and almost no pressure at sensor 2 at any time on the 6 or 7 mile drive we did. Ordered new line (with sensor) and injector, just to know that everything was new. Cleared the codes, drove it about 20 miles... and the P20E9 code popped back up. We have another new pump, and the wiring harness on order, to rule out the wiring harness... but there is extremely limited info on diagnosing this specific code. I can't find the pc/ed manual online for it, and the only diagnostic sheet I can find is for RAM. I did find a 2020 pc/ed manual that shows all the resistance at all the connectors, which is what I'd like to find for our truck so we can check for any shorts before potentially frying another pump. I've also found that the PCM may need to be reprogrammed, or reset, before driving, to learn the new pump... but can't find any support for that.
Before we haul it back to the dealer and potentially pay them to do everything we've already done at a huge markup... any suggestions? or link to the pc/ed for this gen of super duty?
Also, my husband disconnected the computer without saving the data from our last drive before pulling it apart again... so I can't provide that info unfortunately.

thanks for any suggestions or directions!
Also, we are not considering deleting it... we need to be able to trade it in within the next few years

 

Throw that Dorman pump in the garbage where it belongs. There is only one pressure sensor and it is part of that pump. Go buy the Ford pump. There is no relearn or reset that needs to be done after replacement. When activated the pump should produce 70-75psi of pressure.

 

We bought the Dorman because it was the most referenced (in a positive manner) in all the research we did, and it was available same day locally
also, according to all the schematics, there are 2 sensors. One in the pump, one in the feed line

 

The feed line only has a heater element in it. There is no pressure sensor in the line.

 

I'm going off the feed line we ordered saying (with sensor), and our computer showing 'reductant pressure sensor 1' and 'reductant pressure sensor 2' with different voltage and PSI. If there isn't a 2nd sensor, I'm very interested in how the computer is reading one

 

Does anyone know if there is a digital pc/ed floating around for this gen? I don't mind paying the $250 or whatever it is for the disc... but after nearly 3 months, it would be nice to have the diagram to test the wiring this weekend and get the stupid thing running. This is our 2nd low mileage, 'immaculately maintained' 350 in 2 years that has spent more time dead in the driveway than it has being usable, and that doesn't make us very confident in their reliability anymore.

 

I am not sure what diagram you have or what computer you are using but there is no pressure sensor in the line. I'm trying to prevent you from spending your money on parts that are not needed. The P20E9 code only appeared AFTER changing the pump. It was not there before. That to me says the part installed very likely caused the issue as it was the only variable that was changed. The factory parts are far better than aftermarket. I have had very poor luck with Dorman parts.

This is for a 2015.
System Components

The reductant tank stores the reductant.

The reductant tank filler hose is a 2-piece design consisting of a filler hose and a vent hose.

The reductant pressure line supplies the reductant from the reductant pump assembly to the reductant injector. There are different reductant pressure lines for different vehicle wheelbases. The reductant pressure line is heated to prevent freezing.

The reductant pump assembly pumps reductant to the reductant injector. It contains a diaphragm pressure pump, pressure sensor, purge valve, outlet filter, and internal heating element.

The reductant heater and sender assembly contains the pickup tube for the reductant pump module, electric heating element, temperature sensor, and electrode-type level sensor.

The reductant injector is a Pulse Width Modulated (PWM) solenoid controlled directly by the PCM. The injector receives reductant from the reductant pressure line and sprays it into the exhaust stream, where it is mixed into the exhaust gases before entering the catalyst.

The NOx sensor detects levels of NOx in exhaust gases and sends input to the NOx sensor module. For additional information, refer to Section 303-14B.

The NOx sensor module receives input from the NOx sensor and sends it to the PCM. For additional information, refer to Section 303-14B.

 

The number of sensors has absolutely no bearing on what I am asking. I am still curious as to how forscan is giving readings on 2 sensors if 2 sensors don't exist, but that doesn't help figure out why we are continuing to get the code after replacing every piece of the system. Also, I didn't specify before, but the 2nd pump is a warranty replacement, we did not purchase a second one... but if we continue to get the code after replacing it a second time, aside from telling the dealer to buy the truck back and be done with it, we dont know what else to look at. That is what I am asking for help with.

 

I cannot answer as to why Forscan is showing 2 sensors. I don't use that program as I have the factory IDS scan tool. I provided diagrams above of the reductant systems if you want to test circuits. However, with that code only appearing AFTER replacement of the pump with the Dorman unit, I would suspect the pump as the cause of the fault. Again, I recommend replacing the pump with a Ford part if you are going to drop the tank again.

 

I do appreciate the help, truly. Just pregnant and seriously over dealing with issues in these trucks. Our 99' was a bulletproof beast of a truck and these newer ones are on a roll with being garbage. If the dealer hadn't offered us this one below cost to bypass a lawsuit on the previous truck... we'd have gone a completely different direction.

 

I guess my main concern, being as we already have the replacement dorman... do we still blame the pump if it happens again? If it happens again... do we risk another $400 for it to potentially be something else causing the pump to fail? These newer systems are beyond what we've both worked on our whole lives. My husband is an electrician, so he knows voltage and resistance, we just don't know which pins in which plugs to test, to rule out an electrical issue.

 

What does the pressure read with the pump on?

 

After we put it together with the new parts, it was reading 75-80psi while driving. Before we pulled it apart it was reading 0psi

 

To clarify... before we pulled it apart after it threw the code again it was reading 0psi

 

Normal operating pressure is about 73psi for that pump. Code setting criteria as per the PC/ED manual:

The PCM continuously monitors selective catalytic reduction (SCR) system pressure during closed-loop operation. This DTC sets when the system pressure exceeds 650 kPa (88 psi) for 10 seconds, or 790 kPa (115 psi) for 1 second.
It sounds like your pump is functioning, but either has pressure spikes above 115psi or at some point in your drive pressure rises to above 88psi. I would drive it and monitor the pressure and watch to see if the pressure spikes or climbs too high.