ABS light on all the time
I just got this truck and it is currently a mess!!!!! KDP cracked the timing case and leaks all over the place and the oil pan gasket leaks too... not to get off topic... the ABS light is on all the time and I dont know where to start to figure it out why! What should I check first?
Just the ABS or both the ABS and the Brake light?
Also look under the hood and see if you have RWAL or 4WAL, makes a difference where to start.
Code scan for free at Autozone is a good start also.
Also look under the hood and see if you have RWAL or 4WAL, makes a difference where to start.
Code scan for free at Autozone is a good start also.
You would have an abs unit directly under the master cylinder, which should be the rear abs unit, and a seperate one on the drivers side fender, which is the front abs unit. If you do, then you have 4 wheel abs.
You can also look at the front axle, on the inside of each wheel, next to the universal joint. If you have 4 wheel abs, there will be a slotted ring on each axle shaft, with a sensor. This is the tone ring. If you don't have one on each side, then you have rear abs only. You could also take your VIN number into a dealership, and they should be able to tell you.
If your lights are on and you don't seem to have rear brakes, you should pull the rear wheels and drums off, and see how things look. You really need to know if your back brakes are working with an emergency brake issue, or if nothing is working back there.
You can also look at the front axle, on the inside of each wheel, next to the universal joint. If you have 4 wheel abs, there will be a slotted ring on each axle shaft, with a sensor. This is the tone ring. If you don't have one on each side, then you have rear abs only. You could also take your VIN number into a dealership, and they should be able to tell you.
If your lights are on and you don't seem to have rear brakes, you should pull the rear wheels and drums off, and see how things look. You really need to know if your back brakes are working with an emergency brake issue, or if nothing is working back there.
Smokin, just out of curiosity, see if one of your MC reservoirs is empty......if so, replace the rear brake line, rotted thru, BTDT too many times.......... (2) 60" and ( 1 ) 30 " 3/16" brake lines and 2 connectors for an ext. cab, 18" less for a standard cab.
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you guys are the best! I will go have a look when the rain stops out here to let you know what it is for sure. for now it is parked until I pull the rear drums apart! thanks again guys if I am a fresh newb when it comes to working on my own stuff but I know enough to want to learn more! thanks again!
rain gone for now, It is the 4wal abs system (one directly under the master cylinder and one on drivers side fender), is the first step still pull off the back tires and take drums apart to see what condition they are in? I did notice driving it home in the rain yesterday it was locking up the rear brakes when firm pressure was applied if that helps identify it, roads were wet and slick (first rain).
Odd behavior ABS [I]and[/I] Speedometer dash indicators
Hi not trying to hijack this actually want to add to it,
2 weeks ago noticed my ABS and Break light indicator also on, checked master C, was tad low, (2 tablespoons) looked for any obvious wetness, only found built up gunk from the old location of the breather hose, which has since been moved and most of the master cy area has been cleaned, so I feel pretty sure that I have no leaks. Now, I've constant ABS and Brake lights on the dash cluster, and about the same time, I noticed that my speedometer will not report any speed below 20 mph, needle drops like a lead fart, at 21 mph, picks up just fine, I checked the following, I only have rear ABS, rear brakes, (seem to have another 30k in them) all fluid locations, (dry), (see above) all related and some unrelated fuses, (nothing blown) CAB connections,(as the CAB is suppose to collect input for various brake sensors) checked VSS,(Variable Speed Sensor) looks ok, dry and intact (altho non-tested), foot pressure on brake pedal seems ok, altho I'm unsure of what it should feel like, also brakes seem normal, hit em pretty hard in a parking lot! I did notice, while in neutral, when I really applied pressure to it,(brake pedal) it did seem to give a bit, perhaps a little air in the line? but if there is some air, why would that give rise the the cluster lights? In other words, is there a sensor in the MC that warns of air or a squishy pedal? I read somewhere that there's a re-set on the CAB? Also read that if there is a leak within the ABS system, apparently there's a good chance even a trained eye can't see/detect it?
1, where did the fluid go, 2, if there is a CAB re-set where is it? Can or does anyone know how to test the VSS sensor to check it's function, (other than the shotgun approach of replacing stuff until the problem disappears) 3, what's next?
If I figure this out I'll be sure to ad that info , anyone have any idea as to a direction,
Thanks guys
2 weeks ago noticed my ABS and Break light indicator also on, checked master C, was tad low, (2 tablespoons) looked for any obvious wetness, only found built up gunk from the old location of the breather hose, which has since been moved and most of the master cy area has been cleaned, so I feel pretty sure that I have no leaks. Now, I've constant ABS and Brake lights on the dash cluster, and about the same time, I noticed that my speedometer will not report any speed below 20 mph, needle drops like a lead fart, at 21 mph, picks up just fine, I checked the following, I only have rear ABS, rear brakes, (seem to have another 30k in them) all fluid locations, (dry), (see above) all related and some unrelated fuses, (nothing blown) CAB connections,(as the CAB is suppose to collect input for various brake sensors) checked VSS,(Variable Speed Sensor) looks ok, dry and intact (altho non-tested), foot pressure on brake pedal seems ok, altho I'm unsure of what it should feel like, also brakes seem normal, hit em pretty hard in a parking lot! I did notice, while in neutral, when I really applied pressure to it,(brake pedal) it did seem to give a bit, perhaps a little air in the line? but if there is some air, why would that give rise the the cluster lights? In other words, is there a sensor in the MC that warns of air or a squishy pedal? I read somewhere that there's a re-set on the CAB? Also read that if there is a leak within the ABS system, apparently there's a good chance even a trained eye can't see/detect it?
1, where did the fluid go, 2, if there is a CAB re-set where is it? Can or does anyone know how to test the VSS sensor to check it's function, (other than the shotgun approach of replacing stuff until the problem disappears) 3, what's next?
If I figure this out I'll be sure to ad that info , anyone have any idea as to a direction,
Thanks guys
My call would firstly be the VSS in the differential. My 97 has it but only uses it for the RWAL not for speed. But to me it seems like the culprit for you. The VSS is simple resistance test and cleaning the end off. If it has alot of filings on it, I would pull the rear diff cover and inspect for something wearing.
update
Sounds like something I can get my knuckles scraped on, sounds like fun. I'm looking into that first light.. UPDATE Are you Lil Dog talking about the "rear wheel speed sensor"? If so, how the heck does it come out, it wiggles a tad, don't want to break it, or drop dirt into pumpkin? If thats even a possibility. I'll post my findings after, also thanks for the maintenance tip
Thanks Lil Dog
Update Doing lots of reading this am, I think I have located the VSS says it should be on the overdrive portion of the trannym my question is, does a guy have to drain the tranny just to check that sensor? have also found info the Vehicle Speed Control,or Transmission Output Speed Sensor or RWALL? shezz,ya know one would think one name would be enough, seems to be used by the cruse control,and possibly may also be used in conjunction w/ other inputs into the PCM?
I have had the codes read (nothing present), need the DRB ll, or lll for this year of rig)
also I'm going to try the old battery disconnect just for S & G's Update that had no effect
Thanks guys
Thanks Lil Dog
Update Doing lots of reading this am, I think I have located the VSS says it should be on the overdrive portion of the trannym my question is, does a guy have to drain the tranny just to check that sensor? have also found info the Vehicle Speed Control,or Transmission Output Speed Sensor or RWALL? shezz,ya know one would think one name would be enough, seems to be used by the cruse control,and possibly may also be used in conjunction w/ other inputs into the PCM?
I have had the codes read (nothing present), need the DRB ll, or lll for this year of rig)
also I'm going to try the old battery disconnect just for S & G's Update that had no effect
Thanks guys
Last edited by pappyscrapster; Oct 29, 2009 at 04:01 PM. Reason: update
Maybe front wheel bearing
Last time I had this trouble it was the front bearing. It has happend to me twice. Once for each side. I did not change them both at the same time. The drivers side bearing locked up and to be towed to a shop the passenger side I did later at home. Both times the ABS & Brake lite was on. After replacing the wheel bearing assyembly light is out.Now for rear brakes mine are still original at 250k miles and looking god. Think I need to work a little better??? I have replace rotars 2 times on the front and pads about 5 times. May need to check on my back brakes you think????
Good luck.
Good luck.


