Strange Odometer Wrench Reading
 

Hello,

I have a 1998 C280 with around 71k miles. I had the oxygen sensor replaced last week and since then the odometer shows a "wrench" plus "OA1872"- with the last four numbers going up by the mile (the 1872 is where is at the moment). It displays this at all times, not just at start up.

I've searched FSS extensively, but haven't found any relative information or help.

Would you have any insight into this problem? Thank you very much!