I traced a rumbling that occurs right after turning on the key and right before the ABS light comes on to the ABS hydraulic control unit. A couple of months ago, the ABS light came on sporadically, but now it comes on as soon as this rumble occurs and stays on. Any suggestions on what the cause could be and how to fix it? I'm guessing I'll have to take it to the dealer, but suggestions are welcome.

Thanks for your help.

Doug

 

The ABS system runs the pump and cycles the solenoids a few seconds after startup, just to do a self-test.

Having played around with the system in another brand truck, same ABS system, by the way, I believe that rumbling is the ABS pump. The motor on it can go bad. I believe the motor can be changed without major surgery. Getting to it is a major hassle on the SD.

GET THE CODES READ. There is no way to tackle the problem without seeing what the computer is complaining about.

And if you work on it and open any brake lines, there's almost no way to completely bleed the system without a scan tool that can tell the ABS to energize the pump, and cycle the solenoids while you bleed it.

 

Thanks for the reply.

 

Anyone else with any words of wisdom on this one?