I've noticed that overtime I accelerate above 20 mph, I hear what sounds to me like a servo motor turning for just a few seconds. It makes a humm and then all is good. Then sometimes when I brake, I hear the same sounds. But it will be when I am nearly to a stop. It kind of sounds like a blend motor in the dash, but the air keeps coming hot/cold and out the proper vents. Its definitely coming from the passenger side of the truck, I think behind the glove box.
Here is the link to the video of the sound:


My current codes are:

P0340- Camshaft Position Sensor Circuit Malfunction (Replaced CPS 10,000 miles ago)
P0440- Evaporative Emission Control System Malfunction (Comes and goes, I think gas cap is the problem here)
and of course, a couple of O2 sensor codes that have been on for years.



Thanks for any help/ suggestions.

 

what year is this truck? sai and blower are over there......if applicable

 

The only thing I can think of behind the dash might be the satnav disc whirring as you change position and it just happens to coincicide with braking. The only other electro-mechanical noise would be the air pump for the SLS but that is on the chassis below the drivers seat approximately and does pump initially especially with changes in road surface.

 

Sounds like a climate system blender motor trying to open or shut a vent flap.

 

Its a 2000. It does not have SLS nor does it have SAI. It will happen if the blower is on or off.

 

I don't have sat nav either. hmm

 

couldn't you pull climate control fuses/relays to eliminate?

 

Thats a great idea. I will try that.

 

servo