When I start my 2000 ram 5.9, this happenes, brake pedal held on startup and then released I get a noise that sounds like air release (like a puhhhhhhh... sound), this will also happen right when I start it up if I dont hold the brake.

I finally had someone turn the key to run, and stood by the engine and come to find out its the Controller Anti-lock Brake (CAB), the ABS control module right beside the portioning valve. It makes a weird like motor noise (like a little motor that sounds bad as it turns on for a second. If yall dont mind somebody do the same have someone turn the your truck to run and put you hand on the module and see if you feel or can hear any noise from it. If its not normal should I just replace the unit, or is it something fixable?

Page 462 of the 2001 factory service manual (.pdf file) shows info about the CAB. I think my noise is from the pump motor which is under the CAB so maybe I can replace the pump motor without having to program anything. Also I believe ever since I have been hearing this that my braking is not as good as it used to be. I dont have any dash lights on either or any codes.

BTW - I have 4 wheel abs not just rear wheel

-Thanks guys let me know what you think

 

Well I pulled the ABS relay and turned the key to run and the noise was gone, so it is deffinatly the ABS motor. Would the ABS motor be the same from a 2000 5.9 with only rear wheel ABS, since mine is 4 wheel abs. Let me know what yall think.

 

No it isn't unfortunately. You need the abs accumulator motor assembly from a truck that has 4 wheel abs.

 

Thats what I thought, but can any body tell me if there truck does this or not. Before I replace it