300e Check Engine Light w/Transmission in gear
 

Great Website!!!

Today my car starting doing something new. When I put the car into any gear from park, the check engine light goes on. If I move it back to park it still stays on. The transmission seems to be operating as normal, but, I'm paranoid now to travel any long distances. I don't think it's a bad bulb since I didn't have the lights on. If it is not something simple I will have to bring it in to an expert MB mechanic. Where do I begin to diagnose this?

1986 300e
198,900 miles
Purchased the car two years ago.
No major repairs.

On this year, the only thing that will turn on the light is a malfunction of the O2 sensor. I would have this checked.

I have an '88 300E and the same situation occurred with the check engine light. I replaced the Oxygen Sensor and everything was fine after that.