I have a low mileage car (62,842 miles). The Check Engine Light came on today. I undersatnd General Motors diagnostics but I am new to MB. The car appears to be running normally. Is there a way to check what sensor may be the cause? How do I reset the light and/or clear codes? I found a test connector with a reset button & LED. Pressing the button with the engine running turns on the LED, is that normal? Thanks for any help.

Key to Run position
hold button 2/3 secs
count flashes that come back
repeat til all codes have come back.
Write them down..
To clear, after each code comes up , hold button for 7/8 secs
That will clear previous code.
Turn key off 10 sec
On 10 sec
Start
CE will go out

The LED never blinks? LED stays on steady as long as I hold the reset button only. I made a couple of attempts. I waited two 10 sec intervals but CE remains on? Idle may be a little rough but it seems to run about the same as normal.

Try again

There is a phone book of onfo inthe archieves on how to retrieve codes..

Maybe this will help
Key ON, car NOT running..
After HOLDING button for 2 to 3 secs , RELEASE the button and wait..
watch it.. it will start to BLINK .. count the BLINKS
REPEAT to get them ALL

I got it this time - Thanks. It showed a code 31. Then I was able to clear it as you described. Now where can I find out what the codes are? Is there a website or something? Thanks for your help.

http://www.serenitysys.com/MB/ComputerTroubleCodes.htm

Thank you. It lists 'Loose Contact In Intake Air Temperature Sensor Circuit' so now I can check it out. That may take me a while to troubleshoot but a least I'm not working in the dark. I appreciate your quick respones and good advice.

Probably the sensor itself....