Egr valve

[Gill Oruga]

A bad EGR valve will almost always trigger a position code when they go bad. On these CM2350 engines it takes quite a bit to take them out compared to a CM870 or CM871.

It may be a partially plugged DOC trying to constantly regen. I've seen them completely shut down a truck due to severe DOC face plugging and no codes for it.

Go on INSITE and once you stablish a connection, go to:

Advanced ECM Data----Aftertreatment History

Now you'll see the last 10 or so regens, DPF pressure and AFM temperature.
You're looking for regen frequency and quality. Is the engine calling for a regen every 8-12 hours? Or is it normal like 45-60 hrs between them?
A somewhat normal max DPF pressure is ...


{part of post corrected by Rawze: ... an average of around 3.0 in-HG or so for a healthy system ... }

... but if you mostly see 5, 7, or 8+ in-HG your DPF is likely plugged and will need to be cleaned/replaced.

Your temperatures should look something like this for normal operation:
DOC ~500* DPF inlet ~1,050* DPF Outlet ~1,100*

You can also see how hot and how plugged up your DPF has gotten on the window below.


One thing you can also try is doing the aftertreatment "reset all" procedure { ... but NOT a DPF replacement procedure.. leave that option alone} ... and record a complete stationary regen. This will make the fuel doser inject normal amounts of fuel in case you had issues with exhaust leaks in the past and it had to compensate. We should be able to tell how fast the temps go up from the catalyst to see if the face is plugged. How the turbo actuation is working and whether the EGR valve is being forced open or not.

If you want to check it while the regen is going, monitor the EGR differential pressure sensor and if it goes over 0.560 in-HG or above, the EGR valve isn't sealing properly or the motor is getting weak, which usually throws a motor overheat code.

The "reset all" procedure is:
Advanced ECM Data-----Aftertreatment Maintenance----Reset Options----All