This happened to me. First step was to replace speed sensor (that's what the scanner said). But my mechanic told me it could end up being a bad/rusted reluctor ring...which it turned out to be. So I just replaced the axle.

It is possible to replace the ring....but it's a difficult job, way above my pay grade. And probably would have been more expensive to have my mechanic go that route.

https://www.youtube.com/watch?v=Xsqy8TeEcA8

So first step is to replace the sensor. If it's still throwing codes, then it's a bad ring.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 160k miles
06 E320 CDI "Rutherford", Black on Tan, 180k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 79k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife