cascadia dd15 cant go over 55mph

Your MCM (Motor Control Module) can’t find find or read or ACM (Aftertreatment Control Module). There is a small chance that it’s a blown fuse,I haven’t felt with a Cascadia, so You May have to look around. There’s two panels to check, your main fuse panel in the cab, (usually under the top of you right side dash). The second will be a 8x2x3 box mounted by your steering column. Look at any fuse that may be marked ACM there should be at least a few.

 

check the fault number. could be this one
https://ddcsn-ddc.freightliner.com/cps/rde/xbcr/ddcsn/1108-13.pdf

 

Yes, no communication with the ACM Aftertreatment Control Module.
That would be the One-Box on the side of the truck.
Deleting modern trucks is a lot more complicated then it use to be.
The internal programming is pretty smart at figuring out if something has been monkeyed with.

 

Other than your spn3464 fmi 31 fault code, all the others are dealing with MCM/ACM/CPC miss communication. 3464 is a fault with your intake valve.

There are 4 wires that connect all three computers to communicate. Either there is a break or short in those wires or your ACM isn’t receiving key and battery power.

Now it’s just a mater of tracing wire harness’ to find the pinch/ rub/ cut. And hope it’s not moisture in the 21 pin connector that has corroded off a pin...

 

4noReason.... I'm having same issues. how do you solved yours?

 

My truck won't go more than 55MPH. DEF blinking red. Went to the shop and they checked all harness from MCM to CPC to ACA, ACM to MCM checked all fuses, tested CPC module. Everything works fine. any ideas.
Thank you

 

55mph is the first derate level, also probably have 25 percent less power.
With the DEF blinking, most likely a DEF quality code.