2004 Mercedes Benz S430 4Matic ABS light on

The ABS light has been on in my 2004 S430 4matic since June 2017. The local dealer had it for 6 months and concluded the drivers side rear wheel sensor is bad. They tried new sensors part # 2205400417 from MB and other vendors but none worked. They told me I need to find a used sensor from a 2004 S430 4matic and that should clear the ABS light. I have tried 2 used sensors that the sellers said came from 2004 S 430. I also replaced the ABS ESP module with a used one but that didn't clear the ABS light. The ODB II code is 0500 


Does this make sense? The new MB part number 2205400417 is not compatiable with my 2004 S 430 4matic?