jeeperjkjeeper

I just noticed today while waiting for my son at the bus stop that my Jeep makes a "beep" or "tone" sound about every 3-5 seconds while at idle. I cannot here it when driving and only starts to make the noise once the Jeep is sitting and idleing for approx 1 min. It sounds to me like a signal is being "bounced" between the rear of the Jeep and the computer. Does anyone else have this noise. Everything runs mint and there are no idiot lights coming on. There is about 3/4 of a tank of gas in it.

km2jk

I have heard something similar when the key is on with the motor off and the hood up. Not sure where it comes from, but seems like the electronics under the hood are making the noise.

WRAITHYJEEP

that would be the electronic throttle checking it's position and resetting

Vernnz

Since this post started as a "Strange Noise" issue...When I shut down in my garage I hear a brief humming sound from under the hood. It only lasts for 2 or 3 seconds after being shut off, but I have no idea what pump or fan could still be running that briefly EVERY time I shut off.

Any Ideas?

WRAITHYJEEP

this could be few things
the throttle checking it's position like above
engine fan spin down
a/c pressure being balanced in the system
or engine computer doing post diagnostics some PCMs make a noise
engine pcm can also continue to run things like a purge valve for the egr system (not sure if JK has one)

WRAITHYJEEP

I'm waiting for a response to this one
maybe more info from op

i wonder if the egr system is switching and they stereo is picking up the voltage pulse

renegadelt1

I think that’s the fresh air blend door closing, mine does it every time I traced it to the heater box.

WRAITHYJEEP

if you drive around with the door closed then yes as it appears that it is vacuum actuated and that releases when the engine is turned off

natural position is open,

hold on starting to second guess myself
i know with the jeep off and vents set to dash i was able to feel a breeze through the vent

when you close the out door air off (set to recirculate) when you turn it to defrost/defog positions it turns off

so yes natural position is open