CEL has to do with emissions, not operational condition of the vehicle. If the O2 sensor has never been replaced, that'll sure do it. The CEL lights when the computer detects that something it is monitoring is "out of range". If the O2 sensor has finally crapped out (125K is pretty impressive!), the fuel trim will be out of range. Unless you're pinging or running hot, you shouldn't have any concerns getting home.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]