Noise when truck is off

[Rebel20]

I have a 2020 Ram Rebel Ecodiesel. I've noticed after turning the truck off, there is a high pitched humming noise which continues for approximately one minute after being off. What is this noise? Also, unsure this is connected but I've noticed after turning the truck off the, fuel milage range to empty drops about 15 miles the next time I start it up compared to when it was parked. The fuel gauge needle will also drop a small yet noticeable amount. Is it possible fuel is being used after the truck is off to perform some sort of emissions function? Thanks for any replies. Still learning this new truck.

 

[Dusty1948]

I have a 2020 Ram Rebel Ecodiesel. I've noticed after turning the truck off, there is a high pitched humming noise which continues for approximately one minute after being off. What is this noise? Also, unsure this is connected but I've noticed after turning the truck off the, fuel milage range to empty drops about 15 miles the next time I start it up compared to when it was parked. The fuel gauge needle will also drop a small yet noticeable amount. Is it possible fuel is being used after the truck is off to perform some sort of emissions function? Thanks for any replies. Still learning this new truck.

The electronic emergency brake motors will initiate approximately 2-3 minutes after the vehicle ignition is switched off and the vehicle is unoccupied. The motors only run for about 5-6 seconds and I would not describe it as a humming sound.

The closest thing to your sound description would be the fuel pump. Why it would continue to run I haven't a clue. Never heard that type a noise on either of the gas motors.

Sorry. This was probably not very helpful.

Best regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33 gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 03 June 2018. Now at: 037108 miles.

 

[Sascwatch]

I have heard the noise aswell and can confirm it is not the electric parking brake. These trucks have so many modules that slowly power down after the truck is shut off it could be many things.

I wouldn’t think any emissions related stuff is going on after shutdown as it would need exhaust flow for that to operate. The fuel pump may continue to run for a short period to keep the system primed, but I’m not sure.

I haven’t taken the time to pinpoint any of the after shutdown noises as I consider them normal with how many systems are on these vehicles nowadays.

Where is the sound coming from? If it’s from near the drivers side rear wheel it would be the fuel pump or def pump.

 

[Rebel20]

I have heard the noise aswell and can confirm it is not the electric parking brake. These trucks have so many modules that slowly power down after the truck is shut off it could be many things.

I wouldn’t think any emissions related stuff is going on after shutdown as it would need exhaust flow for that to operate. The fuel pump may continue to run for a short period to keep the system primed, but I’m not sure.

I haven’t taken the time to pinpoint any of the after shutdown noises as I consider them normal with how many systems are on these vehicles nowadays.

Where is the sound coming from? If it’s from near the drivers side rear wheel it would be the fuel pump or def pump.

The noise happens as soon as the vehicle is shut off and lasts for quite a while so I dont believe its the parking brake. From what I can tell I've pinpointed the noise to passenger side just in front of the rear tire. Just seems strange and not sure the reason fuel level and range to empty changes after the vehicle is shut off.

 

[turkeybird56]

DO U have the Air Suspension in the truck? If U do, truck adjusting at shut down, would be my guess.

 

[Rebel20]

DO U have the Air Suspension in the truck? If U do, truck adjusting at shut down, would be my guess.

No air suspension

 

[Sascwatch]

Could it be the valve that is located in the exhaust downstream of all the emissions stuff? There isn’t much back in that area really.

 

[turkeybird56]

No air suspension

tried.....

 

[Wilsonwanderings]

I have something similar, though I'd describe it as more of a high pitched whine. Noticed it a lot today with the ignition in run while messing with alphaOBD stuff. I hadn't started the truck at all today so it struck me as a bit odd but chalked it up to new vehicle gadgetry. Interior fan was off.

 

[OldMarine]

could be the system cooling off the turbo after shutoff with auxiliary coolant pump. In the old days you had to idle a turbo engine before shutoff to keep coolant flowing for a few minutes to cool turbo. Now you can just shut them off, and the system does the rest.