looking4r230

Hi All,

I recently picked up my 2004 SL55 AMG from a MB Dealer (after they did a service B maintenance - fluid, check belts, etc.), and as I drove off, a check gas cap light came on.

There was no problem before I dropped off the car, and I suspect they may have disconnected a sensor or something during service.

After I stopped the engine, and restarted it, the warning went away. Then I drove it a little bit and then the warning came back. So, I turned off the engine, and started it again. Then I noticed the check engine light was on.

I'm guessing they may have disconnected a sensor --> which may have caused and OBDII event --> which results in the computer tripping the check engine light.

Does anyone know what they may have done?

Any help is appreciated.

Thanks in advance.

dRockSL55

You did actually check the gas cap besides the restarts, correct?
A faulty, loose or missing gas cap allows for an evap emission leak, which can also cause a check engine lamp

looking4r230

Yup, I tried unscrewing and screwing the gas cap.

Anyways, they fixed it by end of the day. My gas cap looks the same (i.e.: not shiny new) so I suspect they did not change the cap or the seal.

The dealer said something about running/testing the car run without any cap at all, which caused a failure, which caused a check engine light…. Sounds odd to me. (i.e.: why would you do that?)

Anyways, thanks for the reply.