There was a thread on this awhile back, but I cannot find it even using the search, but there is some way you can check the check engine light codes by that thing under the hood on the passenger side (on the early W140). I do not remember how to do this, or how to read the codes. Can anyone help?

Though my W140 is running fine, I think the light being on is hurting me selling it. I called one local shop today and she said they would pull the code for $60.00, but I have to let them know a couple of days in advance. I prefer to do it myself if I can.

Any info appreciated.

FYI - the car has a 4.2L V8 (1993 400SEL)