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I have a 2008 Cabrio with 80k miles. When you start the car the abs light and yellow triangle are on. When you roll forward at about 10-15 mph the lights go of for a few second. Then back on again. The codes point to right front wheel sensor. I replaced the wheel sensor. Still the same thing happens. I put the old sensor on my 2009 and it works fine. I check wiring to my abs module and it is fine. I think the module may be bad. Any thoughts?
 

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Discussion Starter #3
With the light on from start I think that would rule out reluctor ring. The car would need to roll first to know there was a fault. If I am wrong about that please let me know.
 

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If the brake light switch is bad I don't think the car will start at all. If it's not the reluctor rings or wheel sensors, it's a fault in the ABS system itself that needs professional attention. :)
 

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Discussion Starter #6
Thanks for the help guys. I ordered a used abs module. I will plug it in before I install it just to make sure everything is good. I will post what I find.
 

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no, no, no, it's bad reluctor rings! i've been driving with the ABS/ESP lights on for 5 years. i live in the rust belt, just outside Chicago. yes, i start the car, the lights are on, i drive a few feet, they go off, and come back on. i, personally prefer the ABS off, it stops the tranny "creep" in drive, and i bet my clutch will last a lot longer without that "creep". if you want a fix, look under your car, rear axles, there's exposed gears that the ABS sensor reads, as the axle rusts, the rings expand then crack, causing the ABS to go "crazy" and shut down.

The ABS module will do nothing, you just flushed your $$$ down the toilet. examine your rear axles, they sell new rings on ebay cheap, if you want to fix it yourself, or axles on ebay for like $120 each, if you're handy, it's a couple hour fix. MB made a bad design, i worked at a place 10 years ago making wheel hubs for GM, and 10 years ago their ABS sensors where SEALED inside the wheel hubs with the wheel bearings!
 

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If the brake light switch is bad I don't think the car will start at all. If it's not the reluctor rings or wheel sensors, it's a fault in the ABS system itself that needs professional attention. :)
the brake switch will prevent the car from shifting out of park, usually when there's water in it and it freezes, i had that happen twice, i had dave schembri call me personally the second time my car locked in park, and we had a conference call with a top smart technician, i had the shifter replaced the first time, there was an issue with the first smarts lacking lubrication, but it turned out to be the brake switch.

you're right, the reluctor rings tend to crack on the rear axles, both of mine are shot, and I LOVE IT! when my ABS worked, i got stuck in a flat parking lot in an inch of snow, no wheel spin, i got stuck going up an overpass during a snow storm, some guy in a dodge hemi pushed me over the top, only way he could get over, i was blocking him :|

if you don't need "modern technology", my ESP worked less than 0.1% of my driving, you'll be OK. don't tailgate and you'll be fine, and if you get snow in the winter, you can do DONUTS! ESP prevents you from doing DONUTS!
 

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Discussion Starter #14
Quick update, I replaced the abs module this weekend. The car still has the same problem. I ordered the brake switch. I will try that when it comes in. I inspected my reluctor rings. They still look new. Fortunately for me the reluctor rings and axles were painted when new.
 

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Quick update, I replaced the abs module this weekend. The car still has the same problem. I ordered the brake switch. I will try that when it comes in. I inspected my reluctor rings. They still look new. Fortunately for me the reluctor rings and axles were painted when new.
Does it ever occur to anyone (anyone?-anyone?) to have the vehicle scanned for fault codes before starting to shotgun parts at a problem? Why does everyone think it is going to be cheaper to throw four or five parts at it that are not needed?

Never mind. Rhetorical question. :D
 

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Discussion Starter #16
The fault codes are showing a right front wheel sensor problem like I mentioned initially. But after replacing sensor and checking wiring I am trying anything.
 

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The fault code may show that the r/f w/s sensor is triggering the code, but have you thought about examining the caliper, brake pads, rotor condition and wheel bearings, to make sure that none of these items are triggering the fault code? Tire size and tire condition could also be another factor. Also, the sensor air gap should be checked as well. Diagnose the cause of the concern, first, and then make the appropriate repair.


Good luck!
 

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The fault codes are showing a right front wheel sensor problem like I mentioned initially. But after replacing sensor and checking wiring I am trying anything.
I don't know what you are using but you need to try a different scan tool. The tool may be lying to you. I would graph all four wheel speed sensors on the scan tool and see what happens, especially at low speeds, and go from there. Any scan tool that can not graph multiple data parameters is pretty much useless.
 

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Discussion Starter #19
The scan tool that s my friends. I think it is a Snap On. But not sure. I will see if it can graph parameters. Thanks for the info. And thanks for all the help.
 
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