Low DEF Pressure FIX

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.

[EnvoyExpress]

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

[firstname]

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.

[claytonmast]

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 👌

[abdalacasrichannel]

Golden video. Def pumps are in back orders and run high at 1200.

[garybennett]

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

[tedfisher]

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.

[JustinPoland-rr]

Thank you for your video very informative and well spoken. This is the problem I’m having with my truck. I am going to try your method thanks.

[tmon]

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

[kwaldbaum]

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

[jeremywillis]

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

[paulpetroulis]

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-ebmw]

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

[sergeytkachuk]

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

[burnjack]

Fault Code SPN 520342 FMI 17 DEF system rationality DEF pump speed high and SPN 4374 FMI 0 DEF system under pressurized, got red stop engine CEL and amber engine CEL and def light flashing with tank full. Truck went into limb mode. What you think will this kind points to the Pressure Relief Valve maybe plugged too? Not hearing anything from the pump and running. Can the pump be run manually by give it 12 volts? to test. I checked and is a 2020 freightliner 114sd detroit HDEP Diesel 12.8l i-6 55k miles 5k hours on engine and the records show that def filter was never replaced witch supposed to be every 3 years i think. What you think? Thanks for your time

[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?

[OpenSesame]

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....

[Wolfci]

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

[benmallaley]

Know anything about a 700r4 transmission ??

[bluedieselsolucoesautomoti]

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