2018 2500 Cummins hissing/air sound

[Nugnug]

I have a 2018 2500 Cummins with only 17k miles on it. The other day, while waiting in line for fuel, a hissing sound started out of the blue coming from the engine bay somewhere. The truck has not thrown a code. It seems to only happen when the truck is at operating temperature, I do not hear it when I start it up cold. I checked the intake hose in the passenger fender to see if it had collapsed, and it had not. It was fine. The air intake hoses are all tight going from the air filter box to the turbo. I can't make it happen consistently. When it happens, it sounds like it is echoing through the whole intake system. It's really odd. Any ideas on what to look for will be appreciated. TIA

 

[Choupique]

Do you have a means to monitor whether or not it is just a regen?

They make lots of "weird" noises as part of normal operation. Regen, warm-up with the exhaust brake, SOx management cycles, etc.

Stationary Regens can sound particularly bad if you aren't familiar with what that sounds like. Warming up with the exhaust brake also sounds pretty obnoxious.

I wouldn't panic yet. You need a way to read what the engine is doing. Any OBD tool can tell you the DPF management state that the engine is in.