Hi guys. Excuse me for nosing in here. If that pump isn't turning off after pressure builds up, the computer module that runs the pump is shorted and must be replaced. This has been a REAL common problem with GM trucks for many years. This is one of the few instances where buying the extended warranty is worth the cost because you know you'll be needing two or three of these computers if you keep the truck for many years.
I suppose internal leakage in the hydraulic controller could prevent the pressure from building so the pump will continue running, but I haven't really heard of that problem. Your mechanic might have the tools to perform a pressure test to see if pressure is building properly. Dealerships have gauges for that purpose.
The same TYPE of scanner is used that is used for the Engine Computer but it must be able to access the ABS Computer. Not all aftermarket scanners can do that although it's becoming more common on the expensive models.
Tuesday, April 5th, 2011 AT 7:26 PM