How to Check the Engine of a Mercedes Benz

1. Locate the diagnostic port on your Mercedes. This data link connection is the gateway into the Mercedes' computer. Location may vary by model. In the 2009 M Class vehicles, for example, it is covered and is located near the hood release. The connection is not covered in 2009 E Class vehicles, but is in a similar location. If you experience any confusion finding the outlet, there is a locator online that can help.
2. Connect your diagnostic scanner to the Mercedes data link connection. The procedure will vary by the brand and type of scanner you own. Consult your scanner's manual for the precise steps.
3. Either turn the Mercedes' electrical system on or start the engine, whichever the instruction for your scanner specify. If your scanner is not the type that self activates, you will need to press the power button and key in the 'read' or 'scan' commands.
4. Read the codes that appear on the scanner. If your 'service engine' light on your dashboard is on, you will see trouble codes. Those should be addressed immediately. If you scroll through the codes, you can find codes that are classed as 'pending.' These are the codes that can help you troubleshoot an engine, if the service light is inactive.
5. Read through your scanner's manual for code meanings. There should be a list of them, usually in an appendix. The scanner's manual may only have generic codes used in all vehicles. Mercedes has supplemental codes that can be found online.