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P20E8 code

197K views 74 replies 31 participants last post by  ford_doctor 
#1 ·
My 2011 F350 just started throwing a P20E8 code. "Reductant Pressure too Low". Can any body tell me what that means. Thanks for the help.
 
#2 ·
Reductant = DEF
 
#4 ·
Reductant Pressure Too Low

Description: The powertrain control module (PCM) monitors reductant pressure as the system primes for injection. If the system pressure does not exceed 350 kPa (51 psi) within 45 seconds after the reductant pump starts, this DTC sets.

Possible Causes:
Damaged reductant pump
Damaged reductant purge valve
Damaged reductant pressure line
Damaged reductant injector
Damaged reductant pressure sensor

Diagnostic Aids The presence of this DTC may indicate that the vehicle is operating in derate mode and may experience a loss of power.
 
#5 ·
I just got my truck back . I dropped it off Monday night and picked it up the following Monday. I
 
#6 ·
Sorry about the incompleat post, my ham fingers hit the wrong button. My truck threw that code and they replaced the reductant tank assy and the reductant heater and sender assy. The code came up a few days after I had the NOX update done. I don't think it can be related but who knows. 20,400 miles still under warrenty
 
#7 ·
Sorry about the incompleat post, my ham fingers hit the wrong button. My truck threw that code and they replaced the reductant tank assy and the reductant heater and sender assy. The code came up a few days after I had the NOX update done. I don't think it can be related but who knows. 20,400 miles still under warrenty
Hi Desert John and tomallen,

I want to step in here and get both of you escalated to your regional customer service managers. They can assist by working directly with your dealership on a resolution for your concerns. To get started, send me a PM with your VIN, dealer, mileage, daytime phone number, and full name.

Reductant = DEF
It means you most likely need a new pump assembly. Either the sensor or the pump itself is bad, and they are an assembly.
Reductant Pressure Too Low

Description: The powertrain control module (PCM) monitors reductant pressure as the system primes for injection. If the system pressure does not exceed 350 kPa (51 psi) within 45 seconds after the reductant pump starts, this DTC sets.

Possible Causes:
Damaged reductant pump
Damaged reductant purge valve
Damaged reductant pressure line
Damaged reductant injector
Damaged reductant pressure sensor

Diagnostic Aids The presence of this DTC may indicate that the vehicle is operating in derate mode and may experience a loss of power.
Thanks for all the great info, gang! I'm sure Desert John appreciates it!

Crystal
 
#13 ·
Yes there is a difference. The exhaust temperature sensor is a thermocouple that measures exhaust gas temperature. The DEF pressure sensor measures fluid pressure.

P20E8 sets under the following conditions:
The powertrain control module (PCM) monitors reductant
pressure as the system primes for injection. If the system
pressure does not exceed 350 kPa (51 psi) within 45
seconds after the reductant pump starts, this DTC sets.
 
#14 · (Edited)
I too have just purchased a 2011 with 166k miles and has the p20e8 code (no other codes)
Definite noticeable power loss (mainly under heavy throttle) and fuel economy loss with that code. I just drove 1100 miles with it on.
Dealer replaced the pump only to the tune of $600
I told them prior to doing this that I've found many cases where other's have done the pump and didn't cure it so I wanted to make sure they understood that if it didn't fix the problem.......I'm not into "throwing parts" at something on the chance it'll fix it.

No kidding.......exactly 1 mile down the road light back on.
So I'm going back in Monday morning; they're a good dealer and I trust they'll take care of me on the $600 in the form of a refund or some sort of free services to make up for it. If not, I'll be disputing the charge on my credit card. I'll post back what I find out next week.

Is there anyone with more experience on this code that can shed light?
(not sure if there's a tank and sending unit as well that could have a problem that would throw that code???)

I"m guessing they'll need to pressure test the system.....and in my mind, it has to either be
-the pump (already replaced & no change)
-a line leak between pump and injector in exhaust
-the injector itself

But what do I know I'm a 7.3 junkie and the tree hugger system is all new to me:)! I understand they're trying to "help our environment" but.....is it REALLY helping our environment?

I really think this 6.7 could be a very reliable strong powerplant if it wasn't for the emssisions junk.
 
#15 ·
not sure if there's a tank and sending unit as well that could have a problem that would throw that code???
I'm pretty sure the pump, sender (actually 3 sensors for fluid level) & tank are serviced as an assembly and it includes the reductant heater.
 
#16 ·
DTC P20E8 Means low DEF pressure detected. This could mean that the system was too slow to build pressure at start up or could not maintain pressure during operation. There are several possible causes however this is a known pattern failure for some earlier build trucks and there is an applicable TSB for this concern.

TSB 11-12-3 Some F-Super Duty vehicles equipped with a 6.7L diesel engine and built on or before 8/3/2011 may exhibit a malfunction indicator lamp (MIL) with DTCs P20E8 and P202D. These codes are set by a small diesel exhaust fluid (DEF) leak internal to the reductant pump assembly. This bulletin and repair does not apply if any other DTC's other than the two listed are present and BOTH CODES MUST BE PRESENT otherwise normal diagnostics must be performed.

Action: Replace the DEF pump assembly
 
#19 ·
Drove for over a week now and all seems well so I guess it was definitely something in the DEF system triggering the MIL
What a PIA this EPA tree hugger stuff is. I'm fairly certain that I will delete all of this stuff before too long. If it leaves me stranded just one time on the highway due to anything with the damn emissions system, I will basically be forced to remove it. We have no emissions in my state and if some A-hole wants to check my truck over and fine me, then it may be the last late model I ever purchase. I'd rather spend $80k building a brand new 7.3 Again, in case it's not clear...........I LOVE FORDS but despise the EPA!
 
#20 ·
Sorry to dig up an old thread, but my 2011 F250 is on it's third DEF pump and I just got another P20E8. I'll be taking it to the dealer tomorrow. This truck is quickly becoming a problem child. What are my options?
 
#22 ·
Driver,

How many miles do you have on your 2011? Probably more to the point, how often dou you fill up with def? Just guessing, maybe that pump runs way too often. It would do that if some errant sensor tells it to do so, or you are constantly driving in conditions requiring def.

My def use varies with load and driving conditions, ranging from a gallon every 700 miles to a gallon every 1,900 miles. Both were rare events, mostly in the gallon per 800-1200 miles.

I don't know if there is poor quality def out there, but boy if you let it dry out some nasty rough crystals form that would chew up any pump. Don't know what would allow it to dry out in the truck unless the cap was not tightly closed or there is some air getting into the pressurized system.
 
#23 ·
did they replace ONLY the pump? Or also the heater, assembly and all?

My P20e8 code required the heater assembly, new hose, and a full cleaning of the tank and all.

Basically what happens is IF the def system gets contaminated it will cause all sorts of issues.....leading to your code.

Only fix is to replace pump, and clean EVERYTHING in that system before putting new pump in and then making sure they tests INCLUDING visual spray test of the system (probly requires pulling the nozzle out of the exhaust).

I chased that code and that's what it finally took.

hope this helps.
 
#24 ·
It iz at the dealer right now. . As far as I know, they never replaced anything but the pump. When they call, I will ask about everything else. My driving habits use a gallon about every 1,200 miles, on average. The truck haz 55,000 miles on it. I have never allowex it to run anywhere near dry.

We got the extended warranty when we bought it. Otherwise, it would have had a DPF delete months ago.
 
#25 ·
It iz at the dealer right now. . As far as I know, they never replaced anything but the pump. When they call, I will ask about everything else. My driving habits use a gallon about every 1,200 miles, on average. The truck haz 55,000 miles on it...
I'm glad your dealership is hard at work on this, EMD_Driver. Let us know when you hear any news; I'll be here if you need me to step in and help.

Crystal
 
#28 · (Edited)
That is what fuel contamination of DEF looks like. Not saying that is what it is but... And, if that is the root cause of you problems they should have discovered that when they replaced the pump. We are REQUIRED to test the DEF for contamination using Oil Test Paper when replacing DEF pumps under warranty.
 
#32 ·
Service rep said they had tested it, both prior times. If the contaminate was floating on top, could they have missed it? I scooped some of it out of the tank, with the end of a pry bar. It is very thick. That's what leads me to believe it is motor oil. I'm contacting Blackstone, to see if they can test it for me.
 
#29 ·
I don't have 1st hand experience with wrenching on the DEF system BUT does the tank, pump assembly, heater, etc. have any chance of collecting/allowing water into it IF a seal is broken at some link/point in the system/

Case and point:
I've just had a larger replacement TITAN fuel tank installed and where the sending unit bolts in is a lower section of the top of the tank........when I filled it full for the first time, it is leaking so have to take it back in to get sorted out.
My point is, water could/can collect there and if I don't get it sealed, will contaminate my diesel over time.
Wasn't sure if the DEF system has any part of it that could get contaminated in sorta the same kind of manner
 
#30 ·
To answer your question - Yes. Any leak, be it a crack in the tank, a bad seal, cracked hose etc. could allow water to enter the DEF tank. This is no different than a fuel tank in essence.

Of course this is a completely different scenario than what is being discussed in this topic... water will dilute the DEF which will cause different codes to be set.
 
#31 ·
I suggested the owner send the sample to Blackstone for an independent verification. When my 6.4 cratered my old Dealer said contaminated fuel right off the bat. I had them pull and seal a sample right then and there. I never heard that again but there was 3+ gallons of fuel in the crankcase. Contaminated oil was never brought up:)
 
#38 ·
Just returned from the dealer. The urea injector has been diagnosed as faulty, along with one other part (the service writer wasn't sure which part). The needed parts have been ordered and the truck will go in next week (due to my schedule, not the dealer's) for the definitive fix. Per the dealer, this will be a warranty repair as the truck is still in the 5/50 emissions warranty. Will update when I find out everything that was done; so far, though, the dealership has been pretty easy to work with. Thanks to Crystal for watching out for me.
 
#40 ·
My check engine light comes on and garage says the code is P20E8. Then the light goes off for a few weeks, comes back on for a day or two and goes back off. This continues for around 6 weeks. I get a recall letter (I believe the same one everyone else is getting for emissions) and take the truck back to dealership. They do the upgrade and check engine light goes off...two days later the light is back on. Back to the dealership where they say I have 2 codes (P164A and P202D). The called 8 days later and said the NOX sensor was bad. Total was $613.00 ($259 for sensor, $319 for labor and $35 for misc. charges??). I told them I have never been so disappointed in a Ford product as I am with this truck. Will I continue to buy Ford trucks? Probably. Will I continue to be disappointed? Hopefully no but I guess only time will tell.
 
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