c350 ABS Pulse
10-16-2019, 01:46 PM
#1
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c350 ABS Pulse
Hello Everyone
My sister has a 2012 C350 that we are having a weird ABS pulse/grind. I have done searches on the web and also on youtube to no avail on any direction to what could be causing the issue. Below is a little background on what has been done:
Originally she took to a dealer because of a shaking when breaking, they told her it was due to a bad wheel bearing and that she shouldn't even drive it back home to California(she was visiting us in Las Vegas when she took to a dealer for inspection). Due to the high cost, and me thinking that a wheel bearing going bad at only 85k I would check it out and see if it were the brakes. After inspection one of the front bearings did seem a little loose so my father and I proceeded to change both side wheel bearings. After this we noticed that we were getting a weird repetitive ABS pulse that would occur even at super slow speeds and very light pressure on the pedal. Along with that the brakes were still shaking when at high speeds and hard pressure was applied, we ordered new rotors for all 4 wheels.
After the rotors were installed and the problem of the pulse of ABS(that sounds slightly like a grind to me, its loud) we decided to pull the fuse for the ABS which resulted in the problem not happening. So we are at the point that 100% of the time when the fuse is in we are getting this pulse which we think is the ABS activating, and 100% of the time when the fuse is OUT the issue is non existent. This is why we are leaning towards something to do with the ABS. When the fuse is in we do not get any lights/notifications of ABS/ESP issue on the dash.
Any direction on this would be greatly appreciated.
Cheers
My sister has a 2012 C350 that we are having a weird ABS pulse/grind. I have done searches on the web and also on youtube to no avail on any direction to what could be causing the issue. Below is a little background on what has been done:
Originally she took to a dealer because of a shaking when breaking, they told her it was due to a bad wheel bearing and that she shouldn't even drive it back home to California(she was visiting us in Las Vegas when she took to a dealer for inspection). Due to the high cost, and me thinking that a wheel bearing going bad at only 85k I would check it out and see if it were the brakes. After inspection one of the front bearings did seem a little loose so my father and I proceeded to change both side wheel bearings. After this we noticed that we were getting a weird repetitive ABS pulse that would occur even at super slow speeds and very light pressure on the pedal. Along with that the brakes were still shaking when at high speeds and hard pressure was applied, we ordered new rotors for all 4 wheels.
After the rotors were installed and the problem of the pulse of ABS(that sounds slightly like a grind to me, its loud) we decided to pull the fuse for the ABS which resulted in the problem not happening. So we are at the point that 100% of the time when the fuse is in we are getting this pulse which we think is the ABS activating, and 100% of the time when the fuse is OUT the issue is non existent. This is why we are leaning towards something to do with the ABS. When the fuse is in we do not get any lights/notifications of ABS/ESP issue on the dash.
Any direction on this would be greatly appreciated.
Cheers
10-17-2019, 12:48 AM
#2
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Good findings given the limited tools you have, but I believe the next diagnostic step will require the MB scan tool (Xentry) so that you can read actual values while this is happening and to figure out the culprit. I am not sure, but maybe the ABS control unit can be reset or its errors cleared. Since the problem is disappearing when you disable the ABS control unit, the question here is whether the unit is faulty or whether it's getting a signal to active while it shouldn't be getting this signal. Again, Xentry and reading the values will answer a lot of questions.
10-17-2019, 03:19 AM
#3
Senior Member
Hello Everyone
My sister has a 2012 C350 that we are having a weird ABS pulse/grind. I have done searches on the web and also on youtube to no avail on any direction to what could be causing the issue. Below is a little background on what has been done:
Originally she took to a dealer because of a shaking when breaking, they told her it was due to a bad wheel bearing and that she shouldn't even drive it back home to California(she was visiting us in Las Vegas when she took to a dealer for inspection). Due to the high cost, and me thinking that a wheel bearing going bad at only 85k I would check it out and see if it were the brakes. After inspection one of the front bearings did seem a little loose so my father and I proceeded to change both side wheel bearings. After this we noticed that we were getting a weird repetitive ABS pulse that would occur even at super slow speeds and very light pressure on the pedal. Along with that the brakes were still shaking when at high speeds and hard pressure was applied, we ordered new rotors for all 4 wheels.
After the rotors were installed and the problem of the pulse of ABS(that sounds slightly like a grind to me, its loud) we decided to pull the fuse for the ABS which resulted in the problem not happening. So we are at the point that 100% of the time when the fuse is in we are getting this pulse which we think is the ABS activating, and 100% of the time when the fuse is OUT the issue is non existent. This is why we are leaning towards something to do with the ABS. When the fuse is in we do not get any lights/notifications of ABS/ESP issue on the dash.
Any direction on this would be greatly appreciated.
Cheers
My sister has a 2012 C350 that we are having a weird ABS pulse/grind. I have done searches on the web and also on youtube to no avail on any direction to what could be causing the issue. Below is a little background on what has been done:
Originally she took to a dealer because of a shaking when breaking, they told her it was due to a bad wheel bearing and that she shouldn't even drive it back home to California(she was visiting us in Las Vegas when she took to a dealer for inspection). Due to the high cost, and me thinking that a wheel bearing going bad at only 85k I would check it out and see if it were the brakes. After inspection one of the front bearings did seem a little loose so my father and I proceeded to change both side wheel bearings. After this we noticed that we were getting a weird repetitive ABS pulse that would occur even at super slow speeds and very light pressure on the pedal. Along with that the brakes were still shaking when at high speeds and hard pressure was applied, we ordered new rotors for all 4 wheels.
After the rotors were installed and the problem of the pulse of ABS(that sounds slightly like a grind to me, its loud) we decided to pull the fuse for the ABS which resulted in the problem not happening. So we are at the point that 100% of the time when the fuse is in we are getting this pulse which we think is the ABS activating, and 100% of the time when the fuse is OUT the issue is non existent. This is why we are leaning towards something to do with the ABS. When the fuse is in we do not get any lights/notifications of ABS/ESP issue on the dash.
Any direction on this would be greatly appreciated.
Cheers
Just to clarify a few things.
Before you changed the wheel bearings, where the shaking like the pulsing, or from side to side in the steering wheel ?
When you changed the bearings, did you buy a complete hub, or only the bearings ?
If you only changed the bearings, did you fit a new magnetic impulse ring, or refitted the old one ? ( look like a seal ring ).
If the impulse ring is not fitted correctly, the ABS and subsequently the ESP might misjudge the signals. As always there is a tolerance on signals, so that might be the reason you don't get an error from the ABS/ESP system, since it's not enough off.
10-17-2019, 08:28 AM
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I agree with Xsever, since it it rare too se such a detailed description. Very observant.
Just to clarify a few things.
Before you changed the wheel bearings, where the shaking like the pulsing, or from side to side in the steering wheel ?
When you changed the bearings, did you buy a complete hub, or only the bearings ?
If you only changed the bearings, did you fit a new magnetic impulse ring, or refitted the old one ? ( look like a seal ring ).
If the impulse ring is not fitted correctly, the ABS and subsequently the ESP might misjudge the signals. As always there is a tolerance on signals, so that might be the reason you don't get an error from the ABS/ESP system, since it's not enough off.
Just to clarify a few things.
Before you changed the wheel bearings, where the shaking like the pulsing, or from side to side in the steering wheel ?
When you changed the bearings, did you buy a complete hub, or only the bearings ?
If you only changed the bearings, did you fit a new magnetic impulse ring, or refitted the old one ? ( look like a seal ring ).
If the impulse ring is not fitted correctly, the ABS and subsequently the ESP might misjudge the signals. As always there is a tolerance on signals, so that might be the reason you don't get an error from the ABS/ESP system, since it's not enough off.
We purchased the kit MB parts recommended which consisted both inner and outer bearings along with what we thought was just an inner seal. I think that is what your saying is the impulse ring. When the hubs installed this would butt up to the dust shield where the speed sensor is mounted.
Are the scan tools user friendly? I’ve used basic OBDII scan tools before but my readings into this it seems this one is more elaborate and can dive into the ABS.
10-17-2019, 10:25 AM
#5
Senior Member
Before changing the bearings it was just the normal shaking as if the rotors were warped, in all honesty I don’t think the bearings were causing this and the dealership was looking for a larger payday.
We purchased the kit MB parts recommended which consisted both inner and outer bearings along with what we thought was just an inner seal. I think that is what your saying is the impulse ring. When the hubs installed this would butt up to the dust shield where the speed sensor is mounted.
Are the scan tools user friendly? I’ve used basic OBDII scan tools before but my readings into this it seems this one is more elaborate and can dive into the ABS.
We purchased the kit MB parts recommended which consisted both inner and outer bearings along with what we thought was just an inner seal. I think that is what your saying is the impulse ring. When the hubs installed this would butt up to the dust shield where the speed sensor is mounted.
Are the scan tools user friendly? I’ve used basic OBDII scan tools before but my readings into this it seems this one is more elaborate and can dive into the ABS.
When you install them, the must be pressed in gently, square to the axis, and with support over the whole surface.
If they in any way have been bend, warped or otherwise abused, they will make trouble.
Xentry/DAS is user friendly, if you are computer minded. It is identical to the dealer software.Talk with menber @pmercury , he delivers a full version, for a fair amount of money. With his install, there also is a personal tutorial, and help with solving problems. Very nice and forthcoming guy.
