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ABS problem, 2002 Ram 2500 4x4, 5.9 gas

09-03-2011, 04:45 AM
Ok, I'm having a problem with the abs system on my truck. No lights come on, but when I come almost to a stop, the abs kicks in, releasing the brakes, and making the noise that they commonly make when you skid on snow/ice/wet pavement and pushing up on the pedal. I've felt this in many vehicles, when the abs was doing what it was supposed to. This is doing it on dry pavement, when I'm at or below 10 mph, and it's caused a couple of 'oh shit!' moments. Searching the posts here, I did try one tip, which was to pull the fuse for the abs. This immediately stopped the problem. However, now the abs light and check engine light are on, as well as the speedo no longer works and the odo doesn't count miles anymore. The speedow is the only annoying part, but I will have to get a state inspection in October, so I need to deal with it pretty soon. Basically, something in the abs system is thinking one or more wheels is locked up(I assume). I know there is one sensor at the top of the rear diff, I think one on each front caliper. Any ideas on what's most likely, or how difficult to fix? My front rotors are warped to shit, not sure if that's a cause, but they've been like that for a little while, since last year towing a heavy trailer from NC to MD. I have new pads and rotors, was just holding off until closer to inspection time to replace. Thanks!

09-17-2011, 02:15 AM
Update: So I figured out my left side caliper was hanging up. It smoked a pad and my rotor. I replaced both calipers, pads, and rotors. Brakes work awesome, but now I do have an abs light and a brake light on. I hooked up the genisys scanner and pulled a datastream while driving. The left wheel speed never changes, the right and rear speed corresponds roughly with the speedo. I know where the speed sensor is, I'll have to remove the caliper/rotor to get to the little bstard and it's allen key bolt. It's pretty friggin rusty there on top of the hub. I can blow/scrape it off as best I can, but is there anything I should worry about when I remove the old one? What I mean is, if anything, say RUST, should fall down the little hole there, is there anything to worry about? Part won't be in til Monday anyway.

Chris Stewart
09-17-2011, 12:44 PM
Check the wire on that sensor to the harness connector.

Good work!

Tony Silva
09-17-2011, 01:03 PM
I've changed abs sensors on alot of vehicles...some were held in by regular bolts, others by torx bolts and some were held in with allen screws. If possible, squirt on a little bit of 'PB-Penetrating Blast' lubricant the day before you are going to change the sensor...spray it....3 or 4 times over a 2 day period prior to removing the allen screw. "P-B" is a lube that also disolves rust...not all the rust, but is just a precausion against stripping the allen screw. Don't worry about anything falling thru the hole once the sensor is removed. If anything goes thru the hole it will fall completely thru it and land on the teeth of the shaft below the shaft spins...whatever may have fallen thru the hole will fall off the teeth. The only thing I would worry about falling thru the hole would be the allen screw...but I don't think that's possible as you gotta remove the bolt to remove the sensor.

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