ABS light on intermittently

shad_68

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The ABS checklight in the dashboard of my Benz sometimes comes on (and stays on) when driving, without any sort of specific pattern or trigger I could identify. I don't think the ABS module itself is broken, because most of the time ABS does work, just every now and then the light comes on and ABS is seemingly disabled.
The Manual states that the light can also indicate that there isn't enough voltage, which results in ABS being disabled. I'm not too good with electrics, could it be caused by an old battery or worn out alternator?
 

SchumacherM

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A 10 second check with a voltmeter at the battery terminals will give you your answer. If you don't have a voltmeter, I'm sure you know someone who deals with electricity and electronics, he's bound to have one. Something above 13.5V is a good reading.

And anyway, a failing alternator or other power supply problems would flash the warning light in the shape of an accumulator/battery.

I'd say one of your ABS sensors at the wheels or simply the wire that connects them to the module is failing. Something I have seen in quite a few Golfs and such.
 

JCE

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The ABS checklight in the dashboard of my Benz sometimes comes on (and stays on) when driving, without any sort of specific pattern or trigger I could identify. I don't think the ABS module itself is broken, because most of the time ABS does work, just every now and then the light comes on and ABS is seemingly disabled.
The Manual states that the light can also indicate that there isn't enough voltage, which results in ABS being disabled. I'm not too good with electrics, could it be caused by an old battery or worn out alternator?

This could also be a sign of needing to have the brake pads replaced. Some manufacturers do this as a warning sign. I would check the Benz forums for more specific info.
 

shad_68

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Nah, the 190 has a dedicated warning light for brake pads.
 

prizrak

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If your brakes are good otherwise then it would be one of the sensors most likely. One of the Audi service advisors did tell me that ABS light can come on if there is a pressure drop in the braking system but you would likely notice that.
 
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