How to Troubleshoot a Mercedes ML350


1. Determine the location of the OBD2 port on your ML350 by feeling around for it below your steering wheel at the top of the driver's side foot well. The diagnostic port will be marked with OBD and will be approximately two inches in width.
2. Plug the OBD2 code scanner into the diagnostic port, then turn on your ML350 so that the engine is idling. If you are having issues with your engine and cannot get it to idle, turn the ignition to the accessories position instead so that the vehicle's interior electronics are activated.
3. Let the code scanner scan for any error codes that will be sent as output by the diagnostic computer in your ML350 and take note of any codes that appear on the display of the code reader.
4. Bring the codes that were displayed to a licensed mechanic, auto parts store or Mercedes dealership to be decoded. All three of these resources will have books and computer records on hand that can tell you if the error code you received is, for example, indicating a failing sensor.