Archived ABS light and RRRRRRR noise

[Treb]

Help! My ABS light came on and now the truck is making a RRRRRRRRRR noise that sounds like a lawnmower. When I look under the hood, it seems to be coming from a little pump of some sort on the firewall just in front of the driver. Turn the key off, keeps RRRRRRR pumping. Had to unplug the connector going to it to make it go off. Is the truck safe to drive? What does this little pump do? Never noticed it before it went bad! It's a 2003 2500 4WD.

 

[Mishkaya]

I am afraid you are hearing the ABS pump. If it is running when you turn the key off, I would thing the ABS unit itself is bad, and not just a sensor somewhere. Your brakes will work fine without ABS, just remember that you don't have it any more and brake accordingly in slippery road conditions. Hopefully someone else will chime in with a way to troubleshoot the unit.

mishkaya

 

[Treb]

Thanks Mish. I thought that would be the case but I don't know much about the braking system, so was afraid I would lose pressure at some point (and thus brakes). I have the detailed factory shop manual for my old '94, but not for the '03. Sounds like a good time to make the investment.

 

[ToolManTimTaylor]

Help! Turn the key off, keeps RRRRRRR pumping. Had to unplug the connector going to it to make it go off.

What electrical accessories are installed on the truck? Alarm? The ABS pump should not be running key off and truck sitting there. Sounds like it is being A: Backfed somehow by an inadvertant accessory connection that is supllying power from the key off side of things and feeding power to the key on side of things on that particular circuit. B: There is an obvious issue with the control module itself or a wheel speed sensor that is telling the module to pump to pump.

 

[Treb]

The only accessory on the truck that has power to it is the thing that plugs into the back of the radio set that lets me plug my ipod in and control it like a CD changer. Hadn't thought about that, but I don't know why it would keep going when the key is off. Here's a question, though, if the pump is pumping, why wouldn't it make the brake pulse? Unless the pump is also not pumping, just trying. . . .



I've been running with it unplugged, but I don't have speedo or odo either now that it's unplugged. Speedo / odo works fine with it plugged in. Does that mean it's NOT the rear wheel speed sensor?

 

[Treb]

okay, removed the Ipod thing, still have the same problem. Went to O'Rielly's and plugged it into their ODB fault code thing. Found the following codes:



P0948 (hyd pump relay circuit high)

C2B10

C0101

B0070

B0030



Can't find anything on these latter 4 at all, and all I could find on the first one is the description. Any of these codes mean anything to anybody? I cleared them and the only one that came back was B0030. Had the P0050 on before I started and cleared it and all the others showed up. P0050 is the speed sensor error. I assumed I just had that one because I took the harness loose and had no speedo / odo.

 

[paulsmith]

My driver just called (from 200 miles away) he just had the same problem. He even disconnected the batteries to ee if would "reset" but as soon as the batteries were re-connected, the pump started to run again. I had him Pull the fuse... .

Truck is 100% stock 2001 3500 6 speed. (350,000 miles)

any suggestions?

 

[Treb]

All I can offer is bad news. After several trips to the dodge dealer where they replaced the wiring harness and some sensors first, it finally ended up being the brake controller that they had to replace for around $700. . . .