Ok, I disconnected the battery...the CEL went out. Took it for a drive, enough to get it up to operating temp, and tested the Duty Cycle again, and this time it is showing normal percentages...jumps around between 43%-53% at idle and 2500 rpm. Also, the check engine light hasn't come back...

Not sure what to think at this point...I guess I should just keep driving and see if the light comes back on?

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Current cars:
2000 ML55 AMG, 174k miles
2003 C240 T-Modell, 202k miles
1995 S320, 207k Miles