Another ABS/TCS Moser 9" problem (not caused by bumps)
05-22-2006, 09:59 AM
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Another ABS/TCS Moser 9" problem (not caused by bumps)*** FIXED!! I was readng the other thread but it doesn't seem to cover my problem so thought I would start a new one.
I got my Moser 9" (4 channel) installed this weekend and I'm breaking it in now. I reprogrammed with LS1Edit for 4.11's before I installed, so I'm ruling that out as part of the problem but thought it is worth mentioning.
SOoo....I'm having a problem with the ABS/TCS system. I was able to re-install my old sensors with no problem and when I start the car everything is OK. But as soon as I move forward the "LOW TRAC" light kicks on. When I hit the brake I can feel the ABS kicking in. When I stop completely the LOW TRAC light turns off and all is OK. After driving around for a bit (5 minutes or so) the "ABS INOP" light kicks on and TCS turns off (it won't turn on if I try the switch). The weird thing is that I can feel the ABS trying to work when I brake even though it says ABS INOP - it uses ABS for a short time and then quits trying (I can feel the difference in the brake pedal --- as I come to a stop the ABS turns off and the brake feels "normal"). If I drive at higher speeds for a while the "BRAKE" light turns on and ABS doesn't try to work at all anymore.
Brakes are working, just goofy. I've tried cleaning the ABS sensors a couple of times and reseated the wires several times. I also checked and it is not throwing any DTC's that Autotap can detect. I'm afraid that there is a problem with the reluctor ring (?) for the ABS within the wheel. At the very least it seems that the sensor is not reading it correctly but no error with the sensor is being caught by the computer (no DTC's).
Thoughts?
I got my Moser 9" (4 channel) installed this weekend and I'm breaking it in now. I reprogrammed with LS1Edit for 4.11's before I installed, so I'm ruling that out as part of the problem but thought it is worth mentioning.
SOoo....I'm having a problem with the ABS/TCS system. I was able to re-install my old sensors with no problem and when I start the car everything is OK. But as soon as I move forward the "LOW TRAC" light kicks on. When I hit the brake I can feel the ABS kicking in. When I stop completely the LOW TRAC light turns off and all is OK. After driving around for a bit (5 minutes or so) the "ABS INOP" light kicks on and TCS turns off (it won't turn on if I try the switch). The weird thing is that I can feel the ABS trying to work when I brake even though it says ABS INOP - it uses ABS for a short time and then quits trying (I can feel the difference in the brake pedal --- as I come to a stop the ABS turns off and the brake feels "normal"). If I drive at higher speeds for a while the "BRAKE" light turns on and ABS doesn't try to work at all anymore.
Brakes are working, just goofy. I've tried cleaning the ABS sensors a couple of times and reseated the wires several times. I also checked and it is not throwing any DTC's that Autotap can detect. I'm afraid that there is a problem with the reluctor ring (?) for the ABS within the wheel. At the very least it seems that the sensor is not reading it correctly but no error with the sensor is being caught by the computer (no DTC's).
Thoughts?
Last edited by KCRickSS; 05-24-2006 at 08:12 PM.
05-22-2006, 02:25 PM
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Thanks Scott! That was exactly what I was wondering. I was thinking it wasn't a bad sensor but it was reading it incorrectly since it is OK until I start moving. I'm not sure how easily I can measure the gap but I'll try removing the washer on the sensor bolt (or get a smaller washer) and see if that fixes things.
BTW, I found out that ATap doesn't scan the ABS/TCS so that explains the lack of codes. I tried stopping at Autozone and they said their scanner doesn't check ABS either (damn!).
BTW, I found out that ATap doesn't scan the ABS/TCS so that explains the lack of codes. I tried stopping at Autozone and they said their scanner doesn't check ABS either (damn!).
05-23-2006, 10:29 AM
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I don't have a good way to check the gap but I played around with it a bit. I tried to get the sensor to sit deeper in the backing plate for both sides but that didn't change anything.
I also run a DMM to test the voltage when I spin the wheel. I was getting .2 V AC reading when sitting still and it moved to .3 when I hand spun the wheel (spinning pretty slow). So I think I'm getting some juice from the sensor itself but I'm honestly not an expert with the DMM or what amount of juice is enough.
Any other ideas out there? Is there a standard ABS Sensor replacement I can try? For now I've got it unplugged to avoid the ABS running all the time while driving in town. I wouldn't mind not having ABS so much if I didn't paid extra for ABS in the first place.
I also run a DMM to test the voltage when I spin the wheel. I was getting .2 V AC reading when sitting still and it moved to .3 when I hand spun the wheel (spinning pretty slow). So I think I'm getting some juice from the sensor itself but I'm honestly not an expert with the DMM or what amount of juice is enough.
Any other ideas out there? Is there a standard ABS Sensor replacement I can try? For now I've got it unplugged to avoid the ABS running all the time while driving in town. I wouldn't mind not having ABS so much if I didn't paid extra for ABS in the first place.
05-23-2006, 10:43 AM
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A couple other tidbits. To clarify, both wheels returned the same voltage when measured at the wheel.
Also, TCS/ASR never seems to kicks on when I gas it. I'm still taking it easy on the new rear but I don't feel TCS/ASR at all when I slowly roll the throttle. ABS is ALWAYS on when I brake until I hit highway speed and the brake light turns on - then it disengages itself.
Also, TCS/ASR never seems to kicks on when I gas it. I'm still taking it easy on the new rear but I don't feel TCS/ASR at all when I slowly roll the throttle. ABS is ALWAYS on when I brake until I hit highway speed and the brake light turns on - then it disengages itself.
05-23-2006, 11:04 AM
#6
So you had a DMM on the speed sensor itself, one probe on each prong, measuring A/C voltage as you turned the wheel?
I really wish someone had the answer to this.
I have a similar problem albeit with a 12 bolt and the ABS INOP/ASR OFF lights are on all the time. I went on All Data and followed the flow chart, measuring different voltages and resistances through the EBCM and speed sensor...according to All Data I need a new EBCM, that does NOT sound feasible to me AT ALL.
I do not have excessive gap between my sensor and reluctor wheel either. I don't know wtf the problem is. The harness is fine. The sensors are new. And no one can seem to give me an answer. I don't dare take the car to a dealership and have them ream me for 34 hours of diagnostic time, either.
I really wish someone had the answer to this.
I have a similar problem albeit with a 12 bolt and the ABS INOP/ASR OFF lights are on all the time. I went on All Data and followed the flow chart, measuring different voltages and resistances through the EBCM and speed sensor...according to All Data I need a new EBCM, that does NOT sound feasible to me AT ALL.
I do not have excessive gap between my sensor and reluctor wheel either. I don't know wtf the problem is. The harness is fine. The sensors are new. And no one can seem to give me an answer. I don't dare take the car to a dealership and have them ream me for 34 hours of diagnostic time, either.
05-23-2006, 11:18 AM
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Originally Posted by keliente
So you had a DMM on the speed sensor itself, one probe on each prong, measuring A/C voltage as you turned the wheel?
Originally Posted by keliente
I really wish someone had the answer to this......I don't dare take the car to a dealership and have them ream me for 34 hours of diagnostic time, either.
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05-23-2006, 12:28 PM
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Are your tire sizes equal?
What you'd really like, is a DMM that reads frequency;
hook it up to the chopper signal and see whether you
are getting the same frequency off rear and front wheels
at the same road speed.
I got a frequency-reading DMM at Radio Shaft, they are
not that much more expensive (on sale at least). I don't
think DC voltage tells you anything useful, here, other
than "yes, got power"?
What you'd really like, is a DMM that reads frequency;
hook it up to the chopper signal and see whether you
are getting the same frequency off rear and front wheels
at the same road speed.
I got a frequency-reading DMM at Radio Shaft, they are
not that much more expensive (on sale at least). I don't
think DC voltage tells you anything useful, here, other
than "yes, got power"?
05-23-2006, 12:53 PM
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I think the main thing is to see if the Voltage increases as the wheel spins, which both of my rear wheels did. Apparently the magnetic sensor creates an increasing charge as the wheel spins...the faster the spin the higher the voltage. At least that's what I read on a local board. But I'm still hoping for some ABS "expert" to chime in. 
But checking it vs. the front wheels is a good idea...maybe it is off in comparison. ???
But checking it vs. the front wheels is a good idea...maybe it is off in comparison. ???
05-23-2006, 02:11 PM
#10
Originally Posted by jimmyblue
Are your tire sizes equal?
My ABS/ASR went whack when I broke the 10 bolt. The side gear let loose and the sensor kissed the reluctor wheel for a while, so I figured it was the sensor that had gone bad, but it's not. I put a new sensor in and its still giving me left rear speed sensor circuit malfunction...
05-23-2006, 02:13 PM
#11
Originally Posted by KCRickSS
I think the main thing is to see if the Voltage increases as the wheel spins
I thought that the hall-effect sensors read off the teeth of the reluctor. i.e. when the sensor end is over a gap, there would be little or no voltage, and then when the sensor is over a tooth, it would show voltage. Then I thought from there, depending on the frequency of the impulses from the teeth, it could determine how fast you are going and if one wheel is slipping. I may be far off base though.
05-23-2006, 02:40 PM
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Originally Posted by keliente
Would it be the voltage increasing or the frequency?
I thought that the hall-effect sensors read off the teeth of the reluctor. i.e. when the sensor end is over a gap, there would be little or no voltage, and then when the sensor is over a tooth, it would show voltage. Then I thought from there, depending on the frequency of the impulses from the teeth, it could determine how fast you are going and if one wheel is slipping. I may be far off base though.
I thought that the hall-effect sensors read off the teeth of the reluctor. i.e. when the sensor end is over a gap, there would be little or no voltage, and then when the sensor is over a tooth, it would show voltage. Then I thought from there, depending on the frequency of the impulses from the teeth, it could determine how fast you are going and if one wheel is slipping. I may be far off base though.
Did you get someone to read the code for you to find out the "left rear speed sensor circuit malfunction" error? I don't want to pay for the ABS check and none of my OBDII stuff is reading the ABS.
BTW, my tires are the same, so that is definitely not the problem for me.
05-23-2006, 03:02 PM
#13
Originally Posted by KCRickSS
I'm relatively electrically "challenged", but that makes a lot of sense. Can't do it tonight but maybe I'll try re-checking in the next day or two.
Did you get someone to read the code for you to find out the "left rear speed sensor circuit malfunction" error? I don't want to pay for the ABS check and none of my OBDII stuff is reading the ABS.
.
Did you get someone to read the code for you to find out the "left rear speed sensor circuit malfunction" error? I don't want to pay for the ABS check and none of my OBDII stuff is reading the ABS.
.
05-23-2006, 03:39 PM
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Here's a goofy alternative you may have already tried. A friend of mine suggested that I may have zip-tied the wire too tightly or crimped it enough to interfere with the signal. I was going to try undoing all my ties for the ABS wire and taping it temporarily just as a sanity check. I doubt that is it but given your situation it seems possible. ? 
Which scanner are you using? I went to Autozone and the goon there said it wouldn't read ABS, which on second thought I find hard to believe. I should have played dumb and just asked him to scan it without being specific.
Originally Posted by keliente
Yeah I have a decent scanner at home, I was able to read the codes from the ABS controller. It could not however graph or give me readings of each sensor as the car was going down the road. I don't know if it is because there is a problem, or because my car doesn't support this scan tool.
05-23-2006, 03:45 PM
#15
Originally Posted by KCRickSS
Here's a goofy alternative you may have already tried. A friend of mine suggested that I may have zip-tied the wire too tightly or crimped it enough to interfere with the signal. I was going to try undoing all my ties for the ABS wire and taping it temporarily just as a sanity check. I doubt that is it but given your situation it seems possible?
Which scanner are you using? I went to Autozone and the goon there said it wouldn't read ABS, which on second thought I find hard to believe. I should have played dumb and just asked him to scan it without being specific.
It is very possible that the scantool @ autozone can't read ABS codes. It is probably just a generic $20 scanner for pulling emissions codes. Maybe a dealership will scan it for you without charging you an hour of diagnostic time...
05-23-2006, 04:04 PM
#16
Instead of trying to make it work and spending allot of money and time on a component that does nothing but cause issues with RR and drag racing guys, delete it.
Not trying to create a debate, ABS is fine on the average daily driver, it really has no benefit on any performance car. Since most of the guys on these boards are creating drag or road race setups. It does nothing but takes up space, weighs quite a bit and forces you to run tire combinations that you may not want to use. Even changing to tires that are slightly different in size may not set ABS to malfunction but it may be off enough that driving conditions that typically do NOT activate ABS...can activate it. Now you have ABS going off at times that you don't need or want it to!
Food for thought, for the guys buying rear-ends, choosing rears without ABS is typically less expensive.
Removing ABS does NOT effect normal driving. In fact, removing ABS, installing a proportioning valve can actually have more benefits with braking characteristics. The stock setup is biased correctly and setup for ABS to work best. When you change to completely different tire/wheel size, brakes etc you completely change the bias characteristics of the OEM design.
Steve
Not trying to create a debate, ABS is fine on the average daily driver, it really has no benefit on any performance car. Since most of the guys on these boards are creating drag or road race setups. It does nothing but takes up space, weighs quite a bit and forces you to run tire combinations that you may not want to use. Even changing to tires that are slightly different in size may not set ABS to malfunction but it may be off enough that driving conditions that typically do NOT activate ABS...can activate it. Now you have ABS going off at times that you don't need or want it to!
Food for thought, for the guys buying rear-ends, choosing rears without ABS is typically less expensive.
Removing ABS does NOT effect normal driving. In fact, removing ABS, installing a proportioning valve can actually have more benefits with braking characteristics. The stock setup is biased correctly and setup for ABS to work best. When you change to completely different tire/wheel size, brakes etc you completely change the bias characteristics of the OEM design.
Steve
05-23-2006, 04:08 PM
#17
Removing it would be the easy answer...
But I don't really want to get rid of it. I drive my car every day and I am thinking about selling it, I don't want to hide the problem by just making it go away. I want to find out what it is and fix it but it seems to elude me.
But I don't really want to get rid of it. I drive my car every day and I am thinking about selling it, I don't want to hide the problem by just making it go away. I want to find out what it is and fix it but it seems to elude me.
05-23-2006, 04:30 PM
#18
Take it to a dealer and have the EBCM scanned to see what the codes are. If it is a rear-sensor or reluctor ring then it won't be too bad...if it is a front sensor or the EBCM itself, you're getting into quite a bit of money. Taking it to the dealership will cost you probably 50 bucks or so.
Since you checked the simple things already, the costs of reparing it will outweigh the costs of what you will loose when you re-sell the car. I hope you remove the rear-end and re-sell it separate as you certainly won't get the money you put into the rear from the re-sale of the car. Our cars are not worth very much on re-sale.
Since you checked the simple things already, the costs of reparing it will outweigh the costs of what you will loose when you re-sell the car. I hope you remove the rear-end and re-sell it separate as you certainly won't get the money you put into the rear from the re-sale of the car. Our cars are not worth very much on re-sale.
05-23-2006, 04:39 PM
#19
Originally Posted by SJM Manufacturing Inc
Take it to a dealer and have the EBCM scanned to see what the codes are. If it is a rear-sensor or reluctor ring then it won't be too bad...if it is a front sensor or the EBCM itself, you're getting into quite a bit of money. Taking it to the dealership will cost you probably 50 bucks or so.
Since you checked the simple things already, the costs of reparing it will outweigh the costs of what you will loose when you re-sell the car. I hope you remove the rear-end and re-sell it separate as you certainly won't get the money you put into the rear from the re-sale of the car. Our cars are not worth very much on re-sale.
Since you checked the simple things already, the costs of reparing it will outweigh the costs of what you will loose when you re-sell the car. I hope you remove the rear-end and re-sell it separate as you certainly won't get the money you put into the rear from the re-sale of the car. Our cars are not worth very much on re-sale.
This problem started when my 10 bolt broke and obviously didn't go away when I installed my 12 bolt. The sensor seems to be fine and shows appropriate resistance. Going through the AllData flow chart tells me to replace the EBCM...it doesn't make sense to me that breaking a 10 bolt would cause that.
05-23-2006, 04:58 PM
#20
Won't be an inexpensive fix if its the EBCM. If you've exhausted all flow-chart schematics and values are correct, there are no shorts or loose components, it probably is the EBCM as the chart states. Using All data or Mitchells...You've narrowed the problem down quite a bit.
It could be a bunch of things...The circuit is sensitive to electrical interference...I believe the wires are twisted to combat this issue...the easiest check it to just replace the EBCM and see if its the problem...a dealer woudl be able to check that easily...by installing a new unit. If you have another one you can borrow, this is much easier and quicker then going crazy triing to find the culprit since you're already directed towards it being damaged.
It could be a bunch of things...The circuit is sensitive to electrical interference...I believe the wires are twisted to combat this issue...the easiest check it to just replace the EBCM and see if its the problem...a dealer woudl be able to check that easily...by installing a new unit. If you have another one you can borrow, this is much easier and quicker then going crazy triing to find the culprit since you're already directed towards it being damaged.