andreas_ice75

Mercedes SLC ABS Speed Signal Fault

My 2016 Mercedes SLC with a gasoline engine is showing some concerning symptoms. The ABS lamp is illuminated, I'm experiencing traction control issues, and I suspect the ABS system is failing outright. I've scanned the car and it's reporting a speed signal fault. I'm figuring a defective control unit is likely. Anyone else run into similar ABS, speedometer, or odometer malfunction issues on this chassis? I'm trying to gauge the repair cost; I'm estimating 1000€?

4 comment(s)

Whoa, sounds like a mess! I had similar ABS and traction issues on an older E-Class, and it was a nightmare trying to diagnose. A speed signal fault definitely points towards the ABS control unit. Has the ECM been checked too? Sometimes weird electrical gremlins can cascade. Does the speedometer work intermittently or not at all? And is the odometer still racking up the kilometers?

Thanks for the quick reply! The speedometer seems to be working, though I haven't paid super close attention when the ABS light comes on. The odometer is still counting mileage, which is strange. You mentioned the ECM; is there a specific test or reading I should be looking for?

Okay, odometer working is interesting! When my ABS went haywire, it killed everything. It's still highly likely to be the ABS control unit, but the ECM check is to rule out any funky voltage drops or short circuits feeding into the ABS module and causing it to throw the speed signal fault. Honestly, this sounds like it's edging into 'take it to a workshop' territory. They'll have better diagnostic tools to pinpoint the exact fault before you drop 1000€ on a new ABS unit.

Appreciate the insights! I suspected it was getting beyond my DIY skills. Took it to a trusted mechanic today, and you were spot on. The ABS control unit was indeed the culprit. Got it replaced, and everything's back to normal. Cost me about 1000€, just like I estimated. Thanks again!

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