Low DEF Pressure FIX

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In this video we're looking at the Pressure Relief Valve in a GHG14 and GHG17 Detroit Diesel Powered Truck. We'll be talking about how to change them and why it needs to be done from time to time. One of the most common issues is a check engine light from Fault Code SPN 4374 FMI 0. This seems to be very common in equipment running in cold climates.

[@TheDieseler]

It's been a few years now and since this video was posted I have had great luck with reusing these valves. Simply cleaning them with hot water and working the valve seat and spring with a thin pick is all it takes to get them back in working order.

[@idontknowsh..8612]

What size screw did you use to get it out?

[@jadb8452]

Great info, I was in Colorado -10 degree now I got the code 4374-0 about how much was the kit, thanks

[@firstname6208]

people, what he is talking about here is LODS (liquid only dosing system) also if any of the hard plastic lines from the tank to the pump or from the pump to the one box dozer nozzle and back to the pump are kinked (inner liner all jacked up) you can get pressure codes as well. keep the def tank clean. use GOOD def. there is a hydrometer (similar to coolant hydrometer) to measure the def concentration you need 32.5% concentrate. there are many things that can and do go wrong with the def system. good video.

[@garybennett7851]

Wow, you really do a great job of explaining things, thanks so much.

[@TheDieseler]

Thanks a lot Gary! Glad you enjoyed it.

[@jeremywillis2774]

What is the part number to replace the valve and screen and where can I get it?

[@anthonywatford5256]

I don't know who's worse, the EPS, CDC OR IRS. MAYBE THE IRS

[@EnvoyExpress]

No crappy music or needless intro! This help me solve my issue. Thank you and God bless you!

[@longnho7141]

Did you order RS supplies kits to get the value like the video said ? May I ask how do you ordered the kits to get a value ? I have a 2016 freight liner cascadia failed code 4374

[@Wolfci]

Have a code 4374 FMI 4 could this be fixed with this valve ??

[@OpenSesame858]

When replacing I think you're supposed to pressurize the def inlet to inflate the bladder before attaching the line. 90 psi for 3 seconds is what I've seen....

[@celenterprisesltd]

Would this valve have anything to do with these codes? 5246 FMI 0, 4364 FMI 1, 4364 FMI 18 or 3364 FMI 2. I’ve been dealing with this issue for about a year and 3 shops can’t figure it out. I’ve changed everything except the one box. does this every night. All engine lights come on and I stop and do a forced regen and codes clear for the rest of the night. Ever come across this before?

[@TheDieseler]

This valve is most likely not the issue. Check out this video - kzbin.info/www/bejne/e4fXlpuhbqaFbLM It's a run through on what needs to be done to properly diagnose this issue.

[@fredc8618]

4374 fmi 0 came up right after I replaced the DEF pump.. any ideas?

[@darrylmiller9395]

Detroit has a prime def pump service routine you have to run

[@YoungGuttiMoney]

Correct you need to prime the pump

[@paulpetroulis8859]

Thanks, very helpful. We use DDDL. I think I will remove and clean the valve and if necessary put it in my ultrasonic cleaner.

[@JasonCollette-eb8mw]

Do you have a video on replacing these leaking orings I keep hearing about? Its when the whole unit is usually covered

[@kwaldbaum84]

I have a very similar pump on my bluebird visions with isb 6.7 and I’ve found the In tank filter getting sucked in the pick up tube setting code 6485 def pump percentage

[@claytonmast9110]

wicked good video.... just went to service that code... it minus 20c here in Alberta. I figured frozen up but didn't know where. I'm sure relief was stuck open. added warm def. ran unit. after that just like new. thanks 👌

[@benmallaley7004]

Know anything about a 700r4 transmission ??

[@sergeytkachuk6226]

Thanks for your videos. Where can I buy just the valve or what's the part number of it?

[@tmon3409]

Thank you for this info. I got this code on 2018 cascadia and trying to decide if need to going dealer or regular mechanic.

[@bluedieselsolucoesautomoti1802]

hi folks, where can I get the plastic valve? What is the part number please.

[@BVIKL]

Whoever dislike this video are the people from Dealers

[@tedfisher8744]

I wish you would do a video on bleeding one of these pumps. The information you give in your videos is awesome and led me to replace the pump. It wasn't much more money than the kit you talked about. After I installed the pump the system wouldn't build pressure. I pulled a vacuum on the outlet of the pump until I got fluid but after that it was only building 106psi at 1600 rpm. I disconnected the supply to the doser and ran the pump until I got def and plugged it back in. I ran my test again and got the same specs as you. That worked for me but I couldn't find the proper procedure for bleeding the system. Thanks for your help.

[@tedfisher8744]

My low Def pressure code came back spn4374 fmi0. This problem shows up after the front brakes chatter while backing down a incline. This time I went straight and pulled the pressure line off of the doser and ran the ads self test until I got fluid and I plugged it back in. In just a second I heard the pump load up and my pressure returned to normal. Do you have any thoughts on how this could possibly be related to brake chatter or is my problem in the doser because it shouldn't need to be bled manually? Thanks for any help.

[@TheDieseler]

Sorry I didn't see this sooner. As long as the pump is not sucking in air (Submerge the doser supply line in water and watch for bubbles) it shouldn't need to be bled. It's not a deadhead system and DEF and air are always being returned to the tank and purged. If leaking fittings and air are not an issue I would be taking a good look at the wiring to the Doser. This is where the DEF pressure sensor is and that wiring is notorious for rubbing through on things and even on itself. I've even seen wiring that has rubbed completely through the Doser body which allowed it to corrode inside and give false pressure readings.

[@michealdesrosiers3466]

awesome, thanks, very helpful

[@longnho7141]

May I ask what kits part number for rs supplies kits to get the value ? I have 2016 freightliner cascadia ?

[@longnho7141]

May I ask what’s should I ask the dealer part to get that value ? My truck is 2016 freightliner cascadia

[@joelflores9742]

spn 4364 fmi 1 what does this code men

[@tomashernandez9263]

Do you have the part number to this kit?

[@sohailo973]

Respect for your information

[@leeabrahamjr6096]

Eec 61 spn 3251 what does this code mean

[@prashanshan7125]

How does ecu measure pump rpm..?

[@firematter2532]

WAO,,,,, THANK YOU

[@jeancadet5862]

You are the best

[@CosgroveNotts]

This is interesting and I work on Mercedes

[@wd2862]

Thanks

[@GrabinGears]

Mine just came on today with that code and said 25% derate any suggestions? Please help!!!!!

[@transport21]

Just A Trucker what code?

[@GrabinGears]

@@transport21 Spm 4364 Fmi. I've got it fixed since this post. It was the egr actuator dpf pump and something else I forget. Bill was almost 7k

[@mrb5367]

@@GrabinGears have you had problems since??

[@BVIKL]

Wow great video.

[@work2011]

Thanks

[@davinderpalsinghthind291]

Thanks for info

[@marclaroche4732]

Do you have info on Paccar dpf pumps to.

[@TheDieseler]

I have very little experience with Paccar but I believe most of their aftertreatment is basically Cummins.

[@usdpaulp]

Is there a way for me, as an single truck owner, to get the Detroit software without having to pay thousands?

[@TheDieseler]

+usdpaulp I'm pretty sure you can purchase subscriptions to the software from diagnosticlink.nexiq.com/ You would then also need an interface to connect to the truck. As far as cost, I'm not sure what the total would be. I've heard of 3rd party options as well but I'm not familiar with how well they work.

[@firstname6208]

I believe you need to be part of the DDC guild and be part of the dealership network to get ddc proprietary software.

[@jeremyrobertson81]

Check out diesellaptops.com they have all kids of diagnostics for different prices, the CanDo HD mobile unit works with your phone and multiple applications.

[@dell7054]

I got mine of ebay 80 bucks

[@supertrucker1356]

I pulled out, but is def supposed to stop coming out or is this a consistent flow

[@TheDieseler]

If the level in the tank is higher than where the pump is mounted, it will most likely continue to syphon out.

[@supertrucker1356]

@@TheDieseler Ok the same thing happened when i disconnected theines for def doser. Just kept pouring out until i reconnected

[@hellraizer06]

Hey, im currently working on a bus with this exact code. When testing, the pump would run at 3400rpm but pressure would only be about 40psi. We ordered a new def pump so hopefully that fixes it. Your thoughts on it? Also it has a active code 4332/31, is it related to the def system? Should we fix that problem first? Or is this another issuse by itself. Thanks

[@TheDieseler]

+hellraizer06 The other code is related to Regen temps. It's probably unrelated unless you ran a low temp ATD recently and let it run for an extended period. I believe it will sometimes set codes like that in that situation. If you found nothing else wrong with the system, the new pump will probably fix it but most likely because it will come with a new Relief Valve. This may be a good opportunity to try cleaning out the valve in the existing pump.

[@hellraizer06]

Awesome. Thanks for the inpur. Ill check the old pump once i pull it out. Mite also hold on to it as a testing pump. Thanks again.

[@CashNYC]

Or u can just replace the o ring on the vavle and save you're self money

[@TheDieseler]

+Cash_NYC The O-Ring is not the issue. The valve is cracking open below relief pressure.

[@CashNYC]

TheDieseler ok thanks

[@shootMEshootME1]

you guys know you can just eliminate the def system just ask a guy to reprogram the computer

[@Sonicforcesound]

Ed edd where can I get that done and how does it cost?

[@amsttravis5650]

@@Sonicforcesound a guy from Cleveland OH does it . It costs around $1400.

[@anonymoustrucker1782]

@@amsttravis5650 can you have him email me [e-mail]

[@MrMartinconco]

Could you help me, could you give me his info?