One Box issues with simple solutions, How to fix from start to finish SPN 3226 FMI 3 and 4

2012 Freightliner Cascadia EPA10 (with DEF), the current active fault codes SPN 3226 FMI 3 SCR Outlet NOx Sensor Circuit Failed High and SPN 3226 FMI 4 SCR Outlet NOx Sensor Circuit Failed Low.
Once passenger side fairing was removed and after inspection of components. Found the sensor harness was melted and creating a false contact or possible ground issue. Both sensor harnesses were replaced. SCR NOx Outlet Sensor was replaced and also replaced the SCR Outlet Temperature Sensor.
Always perform a parked regen in order to verify repairs.

[@HectorWPadilla]

Dude such a pro, maybe not with the Go Pro 😂, but a pro with how clean and neat you left the wires 😅.

[@fiveandsixwoo4548]

Thank you so much for sharing!

[@jiml9971]

Can you please make a video on the aux power turbine. Inspect and remove thank you sir

[@CarlosDieselElectric]

@@jiml9971 I will try.

[@sergserg2618]

Good work brotha. I have a 2011 Cascadia DD15 SPN3609 Fmi4 DOC already had 2 DOC inlet sensors replaced new harness Im lost on what else. Maybe metal tube plugged up?

[@CarlosDieselElectric]

@@sergserg2618 try using a test ACM. It needs to be EPA10. Also remember you have a main harness that goes from the ACM to the One Box. Your truck should be two rectangular plugs, black and gray. Try using a test ACM first.

[@feimohach]

Pedro thanks sir!

[@feimohach]

When i come to Cali, am looking for yah! 😁👍

[@guillermobarbosa6113]

Where’s you workshop???

[@CarlosDieselElectric]

We are in Montebello, Ca 659 S Maple Ave.

[@GuillermoLopez-m4q]

Hi Pedro, I'm having a problem with code spn3513fmi4. also had a code spn2623fmi8. that one has been resolved with replacement of main engine harness and ecm. but bthe first one brings me to loss of power or advancing, any suggestions? Thank you

[@CarlosDieselElectric]

Is this a Cummins or Detroit engine?

[@twogun214]

I have a 2011 dd15 in a Western Star 4900SA, 280000 miles. When you shut the engine down there will be an intermittent “hissing/vibration” sound coming from the one box area coupled with air pressure loss? Only does it while the air pressure is at or above 90psi or so. One, sometimes both check engine lights are on, sometimes no lights are on? I’ve checked and cleaned the EGR sensor (Delta sensor?) on the top left side of the engine, it was dry and clean. I’m at a loss for what to do next, any help would be appreciated. Thanks

[@CarlosDieselElectric]

EPA10 will do that, the DEF system will purge to clean itself once the truck is turned off. It does that by using the air through the pressure limiting valve towards the DEF metering unit. This is normal, now as for the check engine light. What are the codes? Have you had someone plug in with the DDDL software?

[@twogun214]

@@CarlosDieselElectric I’ve not had anyone plugged in, I just got the truck a few days ago. Drove it 500 miles home, seems to run really good. Got plates today and hooked up a trailer to go for a drive and check lights came on? I’m going to call around tomorrow and see about getting it looked at. Thanks for the response I really appreciate the information you have on your channel, very helpful stuff.

[@mariocontreras1400]

More likely the problem is in the burned harness don’t you think?

[@CarlosDieselElectric]

The sensor is definitely the cause, the plug was melted on both the male and female. the two additional harness are known to give problems because of the location. They sit on top of the One Box so the temperatures will eventually need to be replaced. I typically like to replace both, I see it as I would much rather cover all my bases. Nothing worse then having your customer call you back because the issue came back. Now the truck has to be down and you miss another day of work.

[@seymourknight2297]

Carlos where is your shop?

[@chris76-01]

Any advice for spn 3226 fmi 11 and spn 4796 fmi 31?

[@CarlosDieselElectric]

This is a Freightliner Cascadia with a DD15?

[@chris76-01]

@@CarlosDieselElectric no, 2018 peterbilt 579 with paccar engine. New code added: spn 5298

[@govinlama2731]

❤❤❤❤❤❤❤

[@dianotruckingllc1849]

what part of this is simple lol. Anyways, thanks for the knowledge

[@CarlosDieselElectric]

I agree,

[@chrishotto2003]

How about 3226 fmi 13 any info on what that could be no other codes showing but I’m in 5mph Derate replaced the outlet sensor did a forced regen code still present also def light blinking

[@CarlosDieselElectric]

Check your harness at the One Box. Depending on the year you may have one harness on the box itself or you may have two harnesses on the one box. Start there.

[@chrishotto2003]

@@CarlosDieselElectric it’s a 2017 thank you

[@CarlosDieselElectric]

@@chrishotto2003 Definitely start looking into the harness first. Any corrosion or damaged wires can cause this.

[@chrishotto2003]

@@CarlosDieselElectric so actually after waking up that code has disappeared I have no codes showing on the truck but weird things is I still have a def light blinking lamp light stop engine all on but no codes showing up ?

[@CarlosDieselElectric]

@@chrishotto2003 have someone plug in and see what fault codes were or are inactive.

[@wasiwasitv]

I have code spn 3 226 fmi 3 any advice

[@CarlosDieselElectric]

What year is the truck?

[@kartsmoker]

Had a code for low pressure before Doc on one box?

[@CarlosDieselElectric]

What is the fault code?

[@kartsmoker]

@@CarlosDieselElectric don’t know that. That’s the description of the problem on my mechanic’s computer. Didn’t get the code

[@CarlosDieselElectric]

Ask for the code and I can try to help. Could be something internally wrong. But the code will help. What year is the truck? How many miles?

[@kartsmoker]

@@CarlosDieselElectric 2012 sd114 Freightliner. DD13. Brand new one box with the original sensors. Mechanic says it was one of the pressures sensor before the doc.

[@CarlosDieselElectric]

@@kartsmoker could be. Definitely a good place to start. Tubes, sensors or leaks.

[@mariocontreras1400]

Isn’t it to expensive to be guessing what harness is bad?? Why spend so much money replacing harnesses or sensors that might not be bad😒

[@CarlosDieselElectric]

After you have worked on so many you get familiar with the common problems. The temp sensor being burned and melted has to be replaced and since the plug it was connected to was also melted replacing the harnesses isn’t money wasted or guessing. They commonly go bad because of the heat at the One Box. Sensor runs around $60 and for both harnesses $250-300 so it really isn’t that expensive.

[@srob.8796]

Can you derate with this code ?

[@CarlosDieselElectric]

Technically any fault code can eventually set a derate because it may not allow you to perform a regen.

[@srob.8796]

Thank you been running the truck for a week now both lights on seems like the truck is running normal

[@benraper1677]

Video would be alot easier to follow without that music in the bkgrnd

[@CarlosDieselElectric]

Appreciate the feedback. New videos will not have music 👍🏼

[@jeramiekochlefl-bodner5965]

3226 fmi 20???

[@jeramiekochlefl-bodner5965]

Ghg17 new nox’s temp’s harness, delta p cleaned, no exhaust leaks new dpf clamps. Def doser?

[@CarlosDieselElectric]

@@jeramiekochlefl-bodner5965 what other fault codes are present? Non active and active?

[@Dhindsacalifornia-e9s]

Hi i also have same problem 3226 fmi 20 dd15 cascadia. I put new outlet nox sensor and one box harness. But the check light goes on after 1000 miles plz tel me what is the problem

[@fivestar000]

I have a 4300 it won’t crank to start I didn’t let the gauge cycle I just stared the truck up instantly and it was about to start and half way stopped I got tech out and checked everything and nothing I got a spn 1081 fmi 9 code

[@CarlosDieselElectric]

International? What engine? What year?

[@fivestar000]

@@CarlosDieselElectric Cummins 2015 international

[@CarlosDieselElectric]

What engine?

[@fivestar000]

@@CarlosDieselElectric isb 6.7

[@CarlosDieselElectric]

@@fivestar000 has someone plugged in and checked for fault codes? What codes do you have? Inactive and active