W124 abs light
01-02-2018, 01:21 PM
#1
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1995 Mercedes e320
W124 abs light
Hi guys today I noticed that on my 1995 Mercedes E320 my abs light comes on when I go over railroads but when I turn the car of and turn it back on it’s gone and it doesn’t come back on until I go over a railroad again and I’m trying to figure out what it is.
01-18-2018, 02:37 PM
#3
I have the same issue on the same car. I'm not sure what wheel bearing play would have to do with it. My guess, which I'll investigate eventually, is a wheel speed sensor. The ABS relies on these sensors (one on each front wheel and one on the diff) to monitor wheel speed. If one of them is bad, the light will come on. The sensors are magnets that read the gaps in a metal toothed ring on the wheel hubs and rear differential to monitor the speed of each wheel and the rear dif. Since it's intermittent, or lights when jarred, there may be debris around the sensor causing an erratic reading. It could be as simple as cleaning off metal debris around where the sensor is mounted. That's what I'm hoping for at least. Probably wishful thinking though. The sensors are expensive and just one of the components in the ABS system so keep in mind that other problems can illuminate the ABS warning light. out of curiosity, does your cruise control still work when the ABS light is NOT on?
01-18-2018, 02:56 PM
#4
MBWorld Fanatic!
Well you so nicely explained where and how it all works, the pulse ring on the hubs will change there clearance to the sensor if the wheel bearing has play! W124 is such a basic abs system, it cannot be too difficult to diagnose using some logic thinking
01-18-2018, 03:10 PM
#5
Got it! Thanks for clarifying. Seems like some pretty significant play would have to be present? That does fit the narrative with the bumps though. I'll have to check mine out as well. Thanks again.
01-22-2018, 02:15 PM
#7
MBWorld Fanatic!
I would check for a loose/bad electrical connection to one of the three ABS sensors, in particular, check the connector where they connect to the main wiring harness. The ABS module measures the resistance of each sensor and if it appears incorrect (such as might be caused by a flaky connector being jostled by bumps), the ABS light will come on. Clean each connector with contact clean and see if things improve.
