roklzrd

Ok. Strange on here. My check engine light came on today. No weird sounds. No weird actions. I brought it home and plugged in my Carsoft I980 diagnostic tool. No DTC's. Not one! I have just filled up the tank. Checked the cap. On tight. Runs like a top. Any ideas on what to check next? TIA 2001 S500/ no ABC/automatic/5.0 liter/95k miles.

tusabes

See if your code reader will erase the code and turn off the light . Sometimes takes a couple tries for mine to clear

If the error returns then it's a recurring rather then isolated error

SilberGrau57

The operative statement above is "I have just filled up the tank." The Check Engine light is most frequently associated with the gas filler cap. Even if you put it back on tight, on a 15 year old car, the gasket may be shot. You might need to buy a new gas cap with a fresh gasket. Or somehow, rehabilitate the old gasket on your current cap--silicone spray?

If you can't get the light to reset/go out with your Carsoft I980, you may be able to disconnect the battery/batteries for a brief period, and this will reset it. I am not sure about M-B, but this technique worked to reset the Check Engine on my father-in-law's 2003 Mercury a short time ago.

PhazonPhobe

Might have been a brief ghost code. Try driving it 3 cycles to see if it will reset?

roklzrd

Thanks guys for the input. It took two times clearing the codes with the I980 to get it to "stick". I will keep a check on the gas cap and see if the light returns after the next fill.