Quality ABS Advice
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Quality ABS Advice
OK guys.. ran into a strange one at work today.. thought I'd pass on this information.. it might help one of you one of these days.
We had a 1996 Ford Explorer Sport... Rear wheel drive, manual transmission, four wheel ABS.. pretty much the same setup as the Rangers. Anyways we did lower ball joints and rear brakes to it, and on the test drive noticed the ABS was kicking on at low speeds, even though no wheels were locking up.
Talked to the customer and they admitted it's been doing this since before the work we did, and authorized us to check it out.
Our scanner (genisys) would pull ABS codes (although none were stored) but would not display any ABS information (Manufacturer information not available), so we were at a bit of a loss as to which wheel was causing this.
We found a TSB describing this exact condition, and blaming it on corroded wheel speed sensors, so we replaced the rear diff. sensor due to it's cheapness but that did not help.
Today sold both front sensors (this is not built into the hub, but is seperate because of it being rear wheel drive)... and after installing them the problem was STILL THERE! ARRGGH...
Anyways, like I said based on the symptoms, I felt I could eliminate any wiring or module issues.. no codes and only slow speed operation while applying the brakes. well it just didn't make any sense.
I noticed the front brakes were brand spankin' new.. pads/rotors/calipers so I went through the glove box looking for receipts, hoping to find more clues. I found a receipt for the front brake work at another one of our locations but out of town.. it was all done less than 1,000 miles and three weeks prior, but at least it gave me a good, and cheap way, to replace the rotors (under warranty) as we were teethering on upsetting a very good and loyal customer at this point.
I replaced both front rotors, and PROBLEM SOLVED!
After all was said and done I compared the two "old" rotors side by side, and the tone-ring on one was pressed on about 1/8" further than the other.. in other words it had 1/8" more gap between the ring and the ABS sensor, probably just far enough to cause an intermittant cut-out.
I had closely inspected the ring on the rotors when I had them off doing the front speed sensors, but did not notice any bends or chips or anything out of the ordinary at that time, but then again I didn't compare them side-by-side either.
Needless to say, the customer was very happy to have the problem repaired even though he had to replace a few parts that weren't necessarily bad. We got kind of lucky on this one.. but we were also honest with him as far as his responsibility to buying these parts before-hand.
Anyways.. before you condemn these front speed sensors, take a real close look at the rotors!
We had a 1996 Ford Explorer Sport... Rear wheel drive, manual transmission, four wheel ABS.. pretty much the same setup as the Rangers. Anyways we did lower ball joints and rear brakes to it, and on the test drive noticed the ABS was kicking on at low speeds, even though no wheels were locking up.
Talked to the customer and they admitted it's been doing this since before the work we did, and authorized us to check it out.
Our scanner (genisys) would pull ABS codes (although none were stored) but would not display any ABS information (Manufacturer information not available), so we were at a bit of a loss as to which wheel was causing this.
We found a TSB describing this exact condition, and blaming it on corroded wheel speed sensors, so we replaced the rear diff. sensor due to it's cheapness but that did not help.
Today sold both front sensors (this is not built into the hub, but is seperate because of it being rear wheel drive)... and after installing them the problem was STILL THERE! ARRGGH...
Anyways, like I said based on the symptoms, I felt I could eliminate any wiring or module issues.. no codes and only slow speed operation while applying the brakes. well it just didn't make any sense.
I noticed the front brakes were brand spankin' new.. pads/rotors/calipers so I went through the glove box looking for receipts, hoping to find more clues. I found a receipt for the front brake work at another one of our locations but out of town.. it was all done less than 1,000 miles and three weeks prior, but at least it gave me a good, and cheap way, to replace the rotors (under warranty) as we were teethering on upsetting a very good and loyal customer at this point.
I replaced both front rotors, and PROBLEM SOLVED!
After all was said and done I compared the two "old" rotors side by side, and the tone-ring on one was pressed on about 1/8" further than the other.. in other words it had 1/8" more gap between the ring and the ABS sensor, probably just far enough to cause an intermittant cut-out.
I had closely inspected the ring on the rotors when I had them off doing the front speed sensors, but did not notice any bends or chips or anything out of the ordinary at that time, but then again I didn't compare them side-by-side either.
Needless to say, the customer was very happy to have the problem repaired even though he had to replace a few parts that weren't necessarily bad. We got kind of lucky on this one.. but we were also honest with him as far as his responsibility to buying these parts before-hand.
Anyways.. before you condemn these front speed sensors, take a real close look at the rotors!
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From: Lynchburg, VA
MaxdaRangerGuy.
This is an excellent report. I have this problem on my 99 Ranger (4x4 off-road 3.0L, M5OD, 4WABS). The ABS engages just as I come to a rolling stop. I have replaced the rear sensor and the problem continued. I do not know which one on the front to replace (assuming the sensor is bad) and need to take it in to get the ABS codes read. I cannot recall when the problem began, sometime last summer (I believe I may have a post in here when it first arose) but I replaced front pads and rotors (NAPA parts) last August and can't recall if this is when it started.
I have a few questions on your report and maybe you can suggest next steps for me:
1. Can you describe a little further at what speeds the ABS engaged?
2. Your Genisys scanner did not find any ABS codes. I assume this is a special scanner that attaches to the ABS system and not the OBD II connection? Is this scanner model typical for diagnosing ABS codes?
3. If the sensor had been bad, would you normally have a code available and then would the Genisys be able to diagnose which of the 3 sensors were suspect? What code would you receive if the sensor is bad?
4. I assume you use Ford OE rotors, both the one installed for the original brake maintenance (at the other shop) and the one you installed. Without having the rotor to compare, how can you measure to determine the rotor and ring conform to specs for the ABS sensor.
5. Knowing only the rear sensor configuration, is there an adjustment on the front sensors that allow you to control the gap / spacing to the ring?
Any guidance is appreciated. I am on the verge of taking it to a shop to see if the codes can be read to direct me which sensor to replace.
Thanks, Pat
This is an excellent report. I have this problem on my 99 Ranger (4x4 off-road 3.0L, M5OD, 4WABS). The ABS engages just as I come to a rolling stop. I have replaced the rear sensor and the problem continued. I do not know which one on the front to replace (assuming the sensor is bad) and need to take it in to get the ABS codes read. I cannot recall when the problem began, sometime last summer (I believe I may have a post in here when it first arose) but I replaced front pads and rotors (NAPA parts) last August and can't recall if this is when it started.
I have a few questions on your report and maybe you can suggest next steps for me:
1. Can you describe a little further at what speeds the ABS engaged?
2. Your Genisys scanner did not find any ABS codes. I assume this is a special scanner that attaches to the ABS system and not the OBD II connection? Is this scanner model typical for diagnosing ABS codes?
3. If the sensor had been bad, would you normally have a code available and then would the Genisys be able to diagnose which of the 3 sensors were suspect? What code would you receive if the sensor is bad?
4. I assume you use Ford OE rotors, both the one installed for the original brake maintenance (at the other shop) and the one you installed. Without having the rotor to compare, how can you measure to determine the rotor and ring conform to specs for the ABS sensor.
5. Knowing only the rear sensor configuration, is there an adjustment on the front sensors that allow you to control the gap / spacing to the ring?
Any guidance is appreciated. I am on the verge of taking it to a shop to see if the codes can be read to direct me which sensor to replace.
Thanks, Pat
Last edited by pgw85706; Jun 1, 2007 at 05:00 AM.
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1> The ABS was engaging at speeds less than 15 MPH, especially noticeable that last split second when coming to a complete stop. Once I accelerated past 15MPH no problems were present.
2> Genesis is a scanner made by OTC. It is not the best piece of equipment available, but is plenty capable. My shop purchased it through a local CarQuest and I believe they paid roughly $2400 for it.. including OBDI cables, American, Asian, and European.. and ABS/AIR bag software as well. It pulls ABS codes from the same OBDII port that you pull engine codes, but keep in mind the cheaper "generic" scan tools (like the ones Autozone uses to pull codes) will not interface with the ABS system. Our tool was able to pull codes (well enough to know there weren't any) but would not display any data. It might have been a limitation of the scanner, or a limitation of the Explorer's ABS system.. all I know is it made things a bit of a PITA.
3> I don't have the information in front of me as to what actual codes would have set, but a bad sensor may or may not set a code. If the electrical circuit is compromised, yes it will set a code, but there are other ways the sensor can go bad. In my case the system was simply confusing the intermittant loss of signal from the speed sensor with a wheel locking up, thus engaging the ABS. As far as the ABS computer was concerned, it was working as designed.
I had a similar case right after this one on a Pontiac Grand Am. In this case it would engage the ABS, just like with the explorer, but would shortly after disable the ABS system and turn on the light. It was setting a code for the RF speed sensor. In this case I DID have data, and while watching the wheel speeds I would see the RF read, for example.. 10mph.. then dip to 0 for a couple seconds, then jump back up to 10. After checking it out I found corrosion at the connector (the connector on these is down by the wheel knuckle, not up at front of the vehicle like on the Ford). I pulled the pin out and cleaned off the corrosion, resoldered the pin to the wire, reassembled the connector and plugged it back in. All worked fine then.
4> We used Raybestos rotors. All of our locations are under contract with Raybestos for in-stock brake parts. They are normally very fine parts, this one was just simply mis-manufactured. I was in a bit of a hurry to fix this vehicle, and being out of options I just slapped two new rotors on (on a bit of a guess) and got lucky. I originally had the rotors off when I replaced the sensors and closely examined the rings and found nothing wrong. The reason I didn't find the problem then is because I had one side off at a time and did not compare one to the other. After the fact I examined the two old rotors together and that's when I figured out what had happened. I may have also opted to adjust the rings rather than replace the rotors if I had found the problem beforehand, but like I said.. we just needed it fixed.
5> There is no way to adjust the sensors... well I take that back I guess you could shim it out a bit but that would only work to place the sensor even further away from the ring. What you can do though is adjust the ring location on the rotor. I'll be honest, I don't like doing this because you risk damaging the ring in the process.. or you risk it not fitting as tightly and coming loose down the road if you attempt this, but it is possible to do. It's simply pressed on over the hub.
If your ABS light is not coming on, then it's probably not setting any codes.. you need to be able to read the data. Another thing that's possible is to install a digital graphing multimeter to the sensor wires and read it that way, but that's not a piece of equipment I had available to me at the time.
The shop I work for has recently started getting into diagnostics. For years they have made a fortune doing only brakes and exhaust, but those "good ole' days" are drying up quick and in a hurry. I was hired as the lead diagnostic expert for all seven of our local shops and get several phone calls a day from the various locations on help and advice. Although I'm working with management to decide what equipment we need to get and how.. cost-effective it would be to get such equipment, we're still a little in the stone-age as far as diagnostic equipment goes. Heck we didn't even get the Genesis until a few weeks ago!
Anyways I hope this answers your questions. If you have any more, feel free to ask!
I felt I should add that I do not work for a Ford dealership. I used to up until gas prices really started to jump way up, but business was slow, and after literally everyone in the shop was written up for not producing "acceptible" labor hours.. well they were with Union rights to let anyone go after that for just about any BS excuse. I happened to be one of the unlucky ones. I'm sure all dealerships don't operate like this but after that I had a sour taste in my mouth for working at a dealership anymore.
2> Genesis is a scanner made by OTC. It is not the best piece of equipment available, but is plenty capable. My shop purchased it through a local CarQuest and I believe they paid roughly $2400 for it.. including OBDI cables, American, Asian, and European.. and ABS/AIR bag software as well. It pulls ABS codes from the same OBDII port that you pull engine codes, but keep in mind the cheaper "generic" scan tools (like the ones Autozone uses to pull codes) will not interface with the ABS system. Our tool was able to pull codes (well enough to know there weren't any) but would not display any data. It might have been a limitation of the scanner, or a limitation of the Explorer's ABS system.. all I know is it made things a bit of a PITA.
3> I don't have the information in front of me as to what actual codes would have set, but a bad sensor may or may not set a code. If the electrical circuit is compromised, yes it will set a code, but there are other ways the sensor can go bad. In my case the system was simply confusing the intermittant loss of signal from the speed sensor with a wheel locking up, thus engaging the ABS. As far as the ABS computer was concerned, it was working as designed.
I had a similar case right after this one on a Pontiac Grand Am. In this case it would engage the ABS, just like with the explorer, but would shortly after disable the ABS system and turn on the light. It was setting a code for the RF speed sensor. In this case I DID have data, and while watching the wheel speeds I would see the RF read, for example.. 10mph.. then dip to 0 for a couple seconds, then jump back up to 10. After checking it out I found corrosion at the connector (the connector on these is down by the wheel knuckle, not up at front of the vehicle like on the Ford). I pulled the pin out and cleaned off the corrosion, resoldered the pin to the wire, reassembled the connector and plugged it back in. All worked fine then.
4> We used Raybestos rotors. All of our locations are under contract with Raybestos for in-stock brake parts. They are normally very fine parts, this one was just simply mis-manufactured. I was in a bit of a hurry to fix this vehicle, and being out of options I just slapped two new rotors on (on a bit of a guess) and got lucky. I originally had the rotors off when I replaced the sensors and closely examined the rings and found nothing wrong. The reason I didn't find the problem then is because I had one side off at a time and did not compare one to the other. After the fact I examined the two old rotors together and that's when I figured out what had happened. I may have also opted to adjust the rings rather than replace the rotors if I had found the problem beforehand, but like I said.. we just needed it fixed.
5> There is no way to adjust the sensors... well I take that back I guess you could shim it out a bit but that would only work to place the sensor even further away from the ring. What you can do though is adjust the ring location on the rotor. I'll be honest, I don't like doing this because you risk damaging the ring in the process.. or you risk it not fitting as tightly and coming loose down the road if you attempt this, but it is possible to do. It's simply pressed on over the hub.
If your ABS light is not coming on, then it's probably not setting any codes.. you need to be able to read the data. Another thing that's possible is to install a digital graphing multimeter to the sensor wires and read it that way, but that's not a piece of equipment I had available to me at the time.
The shop I work for has recently started getting into diagnostics. For years they have made a fortune doing only brakes and exhaust, but those "good ole' days" are drying up quick and in a hurry. I was hired as the lead diagnostic expert for all seven of our local shops and get several phone calls a day from the various locations on help and advice. Although I'm working with management to decide what equipment we need to get and how.. cost-effective it would be to get such equipment, we're still a little in the stone-age as far as diagnostic equipment goes. Heck we didn't even get the Genesis until a few weeks ago!
Anyways I hope this answers your questions. If you have any more, feel free to ask!
I felt I should add that I do not work for a Ford dealership. I used to up until gas prices really started to jump way up, but business was slow, and after literally everyone in the shop was written up for not producing "acceptible" labor hours.. well they were with Union rights to let anyone go after that for just about any BS excuse. I happened to be one of the unlucky ones. I'm sure all dealerships don't operate like this but after that I had a sour taste in my mouth for working at a dealership anymore.
Last edited by MazdaRangerGuy; Jun 4, 2007 at 08:41 PM.
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Wow - thanks for the post! I know I am a little late, but I just had the front and rear brakes redone on my '96 B4000 4WD4WABS (SE+) and I now have the very same issue. You have given me something to look at because among the other things changed was the Front wheel rotors (and it was a MAJOR pain getting the right ones!). So you are making me think that maybe there is a gap on the rotors causing the ABS to function improperly.
It is really, really annoying and it causes the vehicle to effectively "slide" a few inches when coming to a complete stop. They never seem to come on any other time. I was considering disabling the front ABS because of it.
R.
It is really, really annoying and it causes the vehicle to effectively "slide" a few inches when coming to a complete stop. They never seem to come on any other time. I was considering disabling the front ABS because of it.
R.
1st Gear
Joined: Jul 2023
Posts: 1
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From: Swamp ass Carolina
OK guys.. ran into a strange one at work today.. thought I'd pass on this information.. it might help one of you one of these days.
We had a 1996 Ford Explorer Sport... Rear wheel drive, manual transmission, four wheel ABS.. pretty much the same setup as the Rangers. Anyways we did lower ball joints and rear brakes to it, and on the test drive noticed the ABS was kicking on at low speeds, even though no wheels were locking up.
Talked to the customer and they admitted it's been doing this since before the work we did, and authorized us to check it out.
Our scanner (genisys) would pull ABS codes (although none were stored) but would not display any ABS information (Manufacturer information not available), so we were at a bit of a loss as to which wheel was causing this.
We found a TSB describing this exact condition, and blaming it on corroded wheel speed sensors, so we replaced the rear diff. sensor due to it's cheapness but that did not help.
Today sold both front sensors (this is not built into the hub, but is seperate because of it being rear wheel drive)... and after installing them the problem was STILL THERE! ARRGGH...
Anyways, like I said based on the symptoms, I felt I could eliminate any wiring or module issues.. no codes and only slow speed operation while applying the brakes. well it just didn't make any sense.
I noticed the front brakes were brand spankin' new.. pads/rotors/calipers so I went through the glove box looking for receipts, hoping to find more clues. I found a receipt for the front brake work at another one of our locations but out of town.. it was all done less than 1,000 miles and three weeks prior, but at least it gave me a good, and cheap way, to replace the rotors (under warranty) as we were teethering on upsetting a very good and loyal customer at this point.
I replaced both front rotors, and PROBLEM SOLVED!
After all was said and done I compared the two "old" rotors side by side, and the tone-ring on one was pressed on about 1/8" further than the other.. in other words it had 1/8" more gap between the ring and the ABS sensor, probably just far enough to cause an intermittant cut-out.
I had closely inspected the ring on the rotors when I had them off doing the front speed sensors, but did not notice any bends or chips or anything out of the ordinary at that time, but then again I didn't compare them side-by-side either.
Needless to say, the customer was very happy to have the problem repaired even though he had to replace a few parts that weren't necessarily bad. We got kind of lucky on this one.. but we were also honest with him as far as his responsibility to buying these parts before-hand.
Anyways.. before you condemn these front speed sensors, take a real close look at the rotors!
We had a 1996 Ford Explorer Sport... Rear wheel drive, manual transmission, four wheel ABS.. pretty much the same setup as the Rangers. Anyways we did lower ball joints and rear brakes to it, and on the test drive noticed the ABS was kicking on at low speeds, even though no wheels were locking up.
Talked to the customer and they admitted it's been doing this since before the work we did, and authorized us to check it out.
Our scanner (genisys) would pull ABS codes (although none were stored) but would not display any ABS information (Manufacturer information not available), so we were at a bit of a loss as to which wheel was causing this.
We found a TSB describing this exact condition, and blaming it on corroded wheel speed sensors, so we replaced the rear diff. sensor due to it's cheapness but that did not help.
Today sold both front sensors (this is not built into the hub, but is seperate because of it being rear wheel drive)... and after installing them the problem was STILL THERE! ARRGGH...
Anyways, like I said based on the symptoms, I felt I could eliminate any wiring or module issues.. no codes and only slow speed operation while applying the brakes. well it just didn't make any sense.
I noticed the front brakes were brand spankin' new.. pads/rotors/calipers so I went through the glove box looking for receipts, hoping to find more clues. I found a receipt for the front brake work at another one of our locations but out of town.. it was all done less than 1,000 miles and three weeks prior, but at least it gave me a good, and cheap way, to replace the rotors (under warranty) as we were teethering on upsetting a very good and loyal customer at this point.
I replaced both front rotors, and PROBLEM SOLVED!
After all was said and done I compared the two "old" rotors side by side, and the tone-ring on one was pressed on about 1/8" further than the other.. in other words it had 1/8" more gap between the ring and the ABS sensor, probably just far enough to cause an intermittant cut-out.
I had closely inspected the ring on the rotors when I had them off doing the front speed sensors, but did not notice any bends or chips or anything out of the ordinary at that time, but then again I didn't compare them side-by-side either.
Needless to say, the customer was very happy to have the problem repaired even though he had to replace a few parts that weren't necessarily bad. We got kind of lucky on this one.. but we were also honest with him as far as his responsibility to buying these parts before-hand.
Anyways.. before you condemn these front speed sensors, take a real close look at the rotors!
My guess is there was a little variation in the insertion depth on the tone plate mounted to the back of the new rotors. Another plausible explanation is that I may have given the rotors "the business" while putting the bearing seal retainer back on which possibly offset the tone plate on both rotors... It's possible that it was my fault.
This post is dam near 16 years old. If I could go back to 2007 and kiss the MAZADARANGERGUY on the lips for posting this, I would. Thank you
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Joined: Mar 2004
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