ABS and BRAKE light on
12-05-2007, 02:32 PM
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ABS and BRAKE light on
The ABS and Brake light are on all the time.... Now.... This first all started when I did my ball joints. When I was all finished w/ the job and went to drive truck, the brake pedal pulsated like the anti-locks were working, except it wasn't slick out.. did this a time or 2 then then lights would come on (disabling ABS) and my braking would be fine. Since then, my right front hub bearing **** out and it came w/ new abs sensor, so I bought one for the other side so that both would be new and still have the same problem. Its not the end of the world because the lights are on all the time and that gives me normal braking, but at the same time it bothers me and I wanna fix it right... so...
12-05-2007, 02:49 PM
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Had the same issue on my old Dakota - obviously a different truck - but the problem I had was the rear speed sensor.... first sensor was replaced, problem came back, then they said the module that the sensor is connected to was bad and it was around $700... won't harm anything, just dont have ABS, which on the Dakota was only rear wheel ABS, so didnt make much difference... Not sure if that helps, are these trucks set up the same with that rear speed sensor and rear wheel ABS?
12-06-2007, 05:01 AM
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I don't know if they're set up the same or not... but I would think that if I had a speed sensor problem, that the speedo would be goofed up??? I'm thinking that the speedo calibrates off of the front abs sensors and the speed sensor
Maybe not? the more I think about it, the more I second guess how it works.......
Maybe not? the more I think about it, the more I second guess how it works.......
12-06-2007, 05:03 AM
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I thought maybe the ABS module too, (pricey!) but I just don't understand why it would work fine before ball joint job and screwey afterward?? I put a MAC mentor diagnostic tool on it and drove it and it showed everything working.... ???????????????
12-06-2007, 06:21 AM
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Try this out, jack up the rear of the truck. (For safety, I would recomend jackstands while both back wheels are off the ground.) Then start it and put it in gear. Let off the brake and with a little throttle,,, your speedometer should show mph increase. if it doesn't,,,,, replace the rear wheel speed sensor. This is how my 99 with 4 wheel ABS acted when the rear wheel speed sensor went bad. The speedo worked fine as long as all 4 wheels were on the ground and rolling,,, but as soon as I lifted the rear of the truck, it would stop working. Below is a copy of one of my old posts when I was trouble shooting mine.
Here is an old post of mine from 9-27-2004 that may help some.
I replaced the rear wheel speed sensor (RWSS) that is located on the top of the rear-end differential and my ABS and BRAKE light have gone off.
Now for a few findings that I came across before replacing it,,,,
*With the rear wheels up on jack-stands, The speedometer did not function at all when in gear at approx 30-35mph. (guesstamated),,,,, however, putting it back down on the ground and driving around,,,,, everything worked fine. (other than ABS and BRAKE light still on)
*When I removed the old RWSS, There was no continuity between the two prongs on the sensor.
I had a few options on what to do,,,
Spend the $60-some bucks for a dealer to put it on their diagnostic gismo (every shop I went to said that only a DC dealership could access the Controller for the Anti-lock brakes. (CAB) and I had already figured out that the CAB does not set any codes in the ECM that are readable by the average DRB scanner.) I figured I would gamble and spend the $33 for the RWSS and the reason for my decision was based on a theory that my front sensors were OK because the speedo and Cruise Control worked fine when all four wheels were on the ground.
This is only my theory and maybe one of our gurus can tell me if I'm correct or not.
On a 4 wheel ABS equipped truck, the CAB must get signals from all 4 of its data gathering sensors in order for it and the speedo and cruise control to function properly.
I also think, this is why the trucks that are equipped with only the Rear Wheel ABS systems have problems with their speedo's and cruise control when the Rear Wheel Speed Sensor goes bad. Evidently this system only uses the two data gathering sensors,,,
The RWSS
And the Transmission Speed Sensor
Does this sound like a fair explanation?
One thing I'm sure of,,,,,,,,,, I don't have those BLASTED idiot lights aggrivating me!
BTW the part number for the RWSS on my 2 wheel drive,,,, 4 wheel ABS equipped 2500 is 56028187AE and this is the same part number for the Rear Wheel ABS only trucks also.
NOTE* However,,, it does appear that the 4 wheel drive trucks have a different part number according to the parts guy I spoke with today. You may want to check and confirm before buying.
Keep in mind that this post was from 2004 and concerned my 1999 2wd / 4wheel ABS truck.
I replaced the rear wheel speed sensor (RWSS) that is located on the top of the rear-end differential and my ABS and BRAKE light have gone off.
Now for a few findings that I came across before replacing it,,,,
*With the rear wheels up on jack-stands, The speedometer did not function at all when in gear at approx 30-35mph. (guesstamated),,,,, however, putting it back down on the ground and driving around,,,,, everything worked fine. (other than ABS and BRAKE light still on)
*When I removed the old RWSS, There was no continuity between the two prongs on the sensor.
I had a few options on what to do,,,
Spend the $60-some bucks for a dealer to put it on their diagnostic gismo (every shop I went to said that only a DC dealership could access the Controller for the Anti-lock brakes. (CAB) and I had already figured out that the CAB does not set any codes in the ECM that are readable by the average DRB scanner.) I figured I would gamble and spend the $33 for the RWSS and the reason for my decision was based on a theory that my front sensors were OK because the speedo and Cruise Control worked fine when all four wheels were on the ground.
This is only my theory and maybe one of our gurus can tell me if I'm correct or not.
On a 4 wheel ABS equipped truck, the CAB must get signals from all 4 of its data gathering sensors in order for it and the speedo and cruise control to function properly.
- Front Left wheel
- Front Right wheel
- RWSS (remember that there is only the one sensor mounted on the pumpkin)
- And the Transmission Speed Sensor which is mounted in the transmission.
I also think, this is why the trucks that are equipped with only the Rear Wheel ABS systems have problems with their speedo's and cruise control when the Rear Wheel Speed Sensor goes bad. Evidently this system only uses the two data gathering sensors,,,
The RWSS
And the Transmission Speed Sensor
Does this sound like a fair explanation?
One thing I'm sure of,,,,,,,,,, I don't have those BLASTED idiot lights aggrivating me!
BTW the part number for the RWSS on my 2 wheel drive,,,, 4 wheel ABS equipped 2500 is 56028187AE and this is the same part number for the Rear Wheel ABS only trucks also.
NOTE* However,,, it does appear that the 4 wheel drive trucks have a different part number according to the parts guy I spoke with today. You may want to check and confirm before buying.
Keep in mind that this post was from 2004 and concerned my 1999 2wd / 4wheel ABS truck.
12-06-2007, 07:14 AM
#6
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Mine has been on for about six years now. Says RF wheel sensor open. Gotta take half the front of the truck off to replace it per the service manual. I personally hate ABS anyway so I don't mind. I probably will fix it when I replace bearings or whatever. I'm sitting at just over 178000 and nine years next month and still got the original brakes all the way around, never been touched.
12-06-2007, 12:45 PM
#7
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To deactivate it, you can to pull the relay!
I had similar occurance, when changed out front wheel bearings. Brakes appeard to work fine, till one time I got a "hard" pedal because the ABS was reading slippage and blocking fluid pressure to the brakes. I had none (on 4 lane hwy at 70 mph). Coasted to stop in the median and finally figured pulling the relay would deactivate the ABS system.
RJ
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12-06-2007, 12:52 PM
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I've pulled the ABS fuse before, and that makes the lights come on too, but when you do that........--> No speedo....
Maybe I will try a rwss.... I just don't see why it would work fine before ball joint job and then be goofed after.... Especially now since I have replaced both ABS sensors... Maybe I will try rwss to see if that cures it.... I dunno...
Maybe I will try a rwss.... I just don't see why it would work fine before ball joint job and then be goofed after.... Especially now since I have replaced both ABS sensors... Maybe I will try rwss to see if that cures it.... I dunno...
12-06-2007, 03:24 PM
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I forget what its called, but my dads 01 had the same issues. Ended up being some module under the hood on the drivers side near the firewall where all the brakes lines come from. Replacing that fixed his issues. Wasn't cheap though, IIRC.
12-11-2007, 08:55 AM
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I would like to know the fix also. It happened when I did my ball joints, or rather after firestone did the alignment. Everything looks ok and I cleaned the connectors that the abs plug into.
My brakes were pulsating as well, kind of scarry if you ask me since there was cars in front of me. On the way home the lights flashed on and off several times before just staying on.
My brakes were pulsating as well, kind of scarry if you ask me since there was cars in front of me. On the way home the lights flashed on and off several times before just staying on.
12-12-2007, 10:04 AM
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Yeah.... I don't know whether to try a RWSS ?? Or... I'm wondering if I may have screwed something up by compressing the caliper pistons???? I've done it a zillion times but maybe I got a piece of crap from inside a brake line pushed back up in one of the modules or brake valves??? Just a thought.... I have seriously thought about cracking all 4 bleeders and just keeping the reservoir full and flowing in all new brake fluid just to see if maybe something stupid like that happened but I doubt it......
12-12-2007, 10:19 AM
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Does your speed not work until you hit 25. I had the same lights on my truck and it was the speed sensor in the rear end. I was driving with no worries then the whole speedometer quit working, then a few weeks after it would come on above 55 and would go up until i hit the pedal then it would come down until i let off then straight back up. It was quite weird and i figured it would be more than just the sensor, but it was the only problem. Around $100 to fix i think.
12-12-2007, 02:35 PM
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Does your cruise control work? Been trying to troubleshoot mine and I've read that the ABS light will come on and stay on when the clock springs are defective in the steering wheel that control your cruise.
That circuit all ties to the brake lamp switch. Maybe that switch is bad causing your problems?
That circuit all ties to the brake lamp switch. Maybe that switch is bad causing your problems?
12-29-2007, 04:21 AM
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Does your cruise control work? Been trying to troubleshoot mine and I've read that the ABS light will come on and stay on when the clock springs are defective in the steering wheel that control your cruise.
That circuit all ties to the brake lamp switch. Maybe that switch is bad causing your problems?
That circuit all ties to the brake lamp switch. Maybe that switch is bad causing your problems?