So my 98 Dodge Ram 1500 now has about 55000 miles on it (I know, not bad), and I've been having several problems with it lately, all of which have been resolved except for this new one. This morning was fine but when I started the truck to leave from work the Brake warning light and ABS warning lights came on and stayed on for the duration of the trip home (about 10 minutes). I thought this was strange so I turned the engine off, waited 5 minutes and turned it back on to see if it was just a glitch but the lights are still on. I checked my brake fluid and am nearly at the full mark, so that's not it. I didn't see any cracks in any of the brake lines so that isn't it either, and I've recently replaced my break pads as well. What do I need to be looking for? I thought I could have either (a) a serious problem and my brake system is screwed, or (b) my sensors are worn out. What do you guys think?

 

I would say sensor. there is an abs sensor in tthe top of the rear end housing. i'd have that checked out.

 

Usually when you have an ABS light and a Emergengy brake light on it is the ABS senson located on top of the rear differential. 2-wheel drive takes part # 56028187AE cost $ 35.50
4-Wheel drive takes part # 5016133AA cost $ 48.35
Hope this helps

 

So I also noticed today that my speedo reads 0 until I get up to about 20 Mph and then suddenly jumps up to the correct speed. This makes me think that my speed sensor is going (has gone) bad. Correct me if I'm wrong but isn't this tied to the ABS sensor or another sensor involving the braking system?

 

So I took it into my local Dodge Dealer for a diagnostic. They confirmed that it was the ABS sensor that was causing the problems, but they also found metal shavings in my rear differential. They told me that in addition to replacing the sensor that they would also replace all the seals/gastics, clean out my rear differential, and add new fluid. For diagnostics, parts, and labor they quoted me $326 for the job. Not sure if I'm getting ripped off or not (mainly cuz I don't know how hard this would have been to do myself). Opinions?

 

i had this happen to me too. it's the speed sensor at the rear axle. it is a magnetic sensor that gets messed up by metal shavings from the gears in the axle. the shavings stick to the axle housing under the sensor by magnetic force and the sensor cannot sense the trigger moving inside like it should. the dealer performed an axle oil change and replaced the speed sensor. the ABS sensor was NOT at fault. this hit me at about 65k miles. the data from the speed sensor not only works the speedometer, but also feeds the ABS system. what the ABS does with it i'm not sure. i think the ABS doesn't work if you're going too slow.

now i have a new code (at 113k miles) indicating that the speed sensor is again having trouble, but this time it's tripped the check engine light and not the ABS. It is an OBDII code p0720 "output speed sensor circuit" which i think is the same sensor.

i have a 2000 ram with a 5.9L and automatic transmission