Cm 2350 derate with spn 1209

[farmtrucknw]

Have a 2017 Prostar with the 415st isx 15 with about 357k miles on it. Had a couple instances where it throws the 1209 code with a derate so I changed out the exhaust back pressure sensor and the egr delta P sensor while I was at it. First trip truck felt a little stronger and thought that must have solved it but threw the same code with derate again. Just like prior times I pulled over, shut truck off and back on on, code goes away and off I go again. What do I need to look at now? My slip joint is leaking from manifold to egr cooler which i need to address but could this be part of problem too? Before I changed sensor out I had a neighbor do a forced regen with incite and it passed fine. Truck does have emissions intact tuning up to 475 hp and has for about a year with no issues. Any help where to look next appreciated.

[tree98]

Check the wiring to the exhaust pressure sensor and also the metal feed tube and sensor block that connects the sensor to the exhaust manifold, they get plugged with carbon. What is that sensor reading in insite with the key on engine off?

[Rawze]

spn1209 is quite vague.

What is the cummins fault code when looking at it in Insite?... and are there any other codes showing both active and inactive?.

[farmtrucknw]

(09-06-2025 )tree98 Wrote:  Check the wiring to the exhaust pressure sensor and also the metal feed tube and sensor block that connects the sensor to the exhaust manifold, they get plugged with carbon. What is that sensor reading in insite with the key on engine off?

With the new sensor, engine off, 98.7 kPa and a voltage of .877 volts. 29.1 inHg and local airport is 29.15 inHg, not sure if that considered close for that sensor or not.

That was checked with my laptop and {3rd party software}. I have to run up to my neighbor for incite to pull codes again.

[tree98]

(09-08-2025 )farmtrucknw Wrote:  With the new sensor, engine off, 98.7 kPa and a voltage of .877 volts. 29.1 inHg and local airport is 29.15 inHg.

The sensor is reading the correct pressure.

[Rawze]

could be crappy delete programming?....
https://rawze.com/forums/showthread.php?...4#pid82904

[farmtrucknw]

(09-08-2025 )Rawze Wrote:  could be crappy delete programming?....
https://rawze.com/forums/showthread.php?...4#pid82904

It's not deleted but it does have a power increase from 415 to 475 hp. Tuning was do e by a large tuner that I have had great luck with on JD equipment and pickups but after reading about all the bad tuning on here that may be the problem. I have to ability to put the stock file back in. It never really felt that strong anyway and I assumed most of that was because of the eaton autoshift protections and the fact it has way too tall of gearing.

[farmtrucknw]

(09-08-2025 )Rawze Wrote:  could be crappy delete programming?....
https://rawze.com/forums/showthread.php?...4#pid82904

Also that's a different truck your thread is linked back too. I have a 2016 prostar 400st and a 2017 415st. I see if I'm gonna have any more of these red motors around I'm gonna need to get incite

[Rawze]

(09-08-2025 )farmtrucknw Wrote:  

(09-08-2025 )Rawze Wrote:  could be crappy delete programming?....
https://rawze.com/forums/showthread.php?...4#pid82904

It's not deleted but it does have a power increase from 415 to 475 hp. Tuning was do e by a large tuner that I have had great luck with on JD equipment and pickups but after reading about all the bad tuning on here that may be the problem. I have to ability to put the stock file back in. It never really felt that strong anyway and I assumed most of that was because of the eaton autoshift protections and the fact it has way too tall of gearing.

what is the engine ser#?... and what is the program name that is in it now.. for all you know, the current programming might not even be compatible.