ABS yelling at me

[britishninja]

hey guys i just replaced lots of parts on my 02 crew cab ls and one of those parts was the wheel hub with the abs sensor. the reason i replaced it was when i would step on the brake it would make a mooing noise at me i was told it was the abs unit. so i replaced the whole hub and unit assembly but it is still making that noise . there are no lights on the dash the fuses are all good and the only code the engine is putting out is p0137 saying 02 sensor circuit low volt bank 1 sensor 2. i don't think that would cause this problem. any ideas or fixes if any one else has experienced the same thing

[HenryJ]

The abs system activating would be a buzzing feel in the pedal when applied. You say you hear a "mooing". Could it be a vacuum booster sound?

Is your vacuum system OK? No fluid in the system? Vacuum reservoir attached?

[britishninja]

The abs system activating would be a buzzing feel in the pedal when applied. You say you hear a "mooing". Could it be a vacuum booster sound?

Is your vacuum system OK? No fluid in the system? Vacuum reservoir attached?

It's the buzzing noise and push back you get when the abs activates mooing was probably abad way to describe it

[HenryJ]

Ah, ok...on the same page now.

Wheel sensors , checked. Speed sensors included. Make sure they are the same if you replaced only one. Tire sizes the same.

Bleed the system. No way for the user to cycle the abs system during the bleed, so do as best you can to make sure the fluid is clean and bled. Work from farthest to closest. If in doubt, do it again.

The module is the usual suspect. Motors usually work, or don't. Beyond that a TechII may be the only way to further diagnose?

[Built2Bend]

Do you have acces to a diagnostic scan tool? Plug it in and moniter the wheel speed sensors when the abs in kicking in that will atlest narrow down to one corner of the truck where the problem is. Dealers and some indipendent shops could do the same test. But will charge.

[ApproachMedium]

ABS units failing on these trucks is a common problem. I wouldn't be surprised if its the module itself and not the sensors, but it pays to check with diag tools first.