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DD15 Engine Brake Issue - Printable Version

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DD15 Engine Brake Issue - armana87 - 02-11-2023

One of my trucks were bypassed in the past and everything has been fine after that (2-300k miles until recently drivers been complaining about his brakes so finally I took it for a test drive and discovered that engine brake is always engaged even at standstill if you hit the throttle you can hear the engine brake cutting the rpm’s drop quick even driving between shifts at low speed..and if you turn the engine brake off from the steering switch everything is normal when driving. This happens when engine warms up and jakes get activated. When he got back to our yard the engine was misfiring because he was driving it with the jakes holding the truck back, after it cooled down it never misfired again.

The only code I show is

SPN 973 FMI 9
SPN 986 FMI 9 (on and off)
SPN 2791 FMI 7 (inactive)


RE: DD15 Engine Brake Issue - Rawze - 02-12-2023

detroits and deleting them = only ending up with a bad delete. Who knows what some moron might have done in that programming.


RE: DD15 Engine Brake Issue - Bengy88 - 02-12-2023

If your mcm was flashed when your truck was deleted then I can guarantee it’s a bad one. The only successful deletes I’ve seen on a dd13 or 15 that doesn’t harm the engine and break turbo shafts is when the acm is the only thing flashed, egr is left active and necessary changes made to the mcm with dddl. Not saying your delete is the engine brake problem but be weary of deleting dd engines as rawze was saying.

If I’m not mistaken the 973 and 986 codes are for engine brake controller. Is this a ghg14 truck by chance? The cpc4 in a ghg14 Cascadia is common for giving issues with very f***** up problems


RE: DD15 Engine Brake Issue - RollinCoal - 02-14-2023

(02-12-2023 )Bengy88 Wrote:  If your mcm was flashed when your truck was deleted then I can guarantee it’s a bad one. The only successful deletes I’ve seen on a dd13 or 15 that doesn’t harm the engine and break turbo shafts is when the acm is the only thing flashed, egr is left active and necessary changes made to the mcm with dddl. Not saying your delete is the engine brake problem but be weary of deleting dd engines as rawze was saying.

If I’m not mistaken the 973 and 986 codes are for engine brake controller. Is this a ghg14 truck by chance? The cpc4 in a ghg14 Cascadia is common for giving issues with very f***** up problems

I only know of 2 people that can actually tune them where they live with no problems (mainly live)
there a pain and already troublesome engines