Issue reading check engine light
 

Hello! I am a new member to this site. I have tried searching for my problem, but can't seem to find anything.

I have a 1993 190E 2.3 (california) with the check engine light on. Some times the light is much brighter than others, but it is always on.
Near the battery is the LED light and the little button to push, that should flash codes. When I press the button, the LED does not come on. I tried sitting in the car while a friend pushed the button, and it made the check engine light on the dash light up brightly until the button was released, but it did not flash.
Is there another way to read the codes?

The car has 116,000 miles on it, and drives well, but vibrates at idle, and hesitates when cold for the first 30 seconds or so. I bought it as an extra vehicle, and don't need it any more, but don't want to sell it with the light on.

Thanks in advnce

Replace OVP
 

It's been my experience that when the Diagnostic Socket doesn't light up, the OVP relay needs to be replaced. The good news is that they are cheap so cheap that you should order two new ones at the same time. I have had new ones fail right out of the box. This is highly unlikely with two and if one happens to fail, send it back but you'll still be able to solve your problem.

Update:
I disconnected the battery and took the OVP relay out this week. After bench testing in, taking the case off and poking around, I put it back in the car. NO MORE CHECK ENGINE LIGHT. But it couldn't keep itself alive when cold.
For whatever reason, the next day it was just fine. Starts and idles cold, no lights, and strangely the exhaust sounds different (??)
The little LED still doesnt work, but since the CEL is out, I dont care.
-Happy camper

CEL will return- sorry!
 

Sorry to say that eventually your CEL will return. When you disconnect the battery, the CEL system turns off until your car has completed 6-8 duty cycles (cold engine to normal operating temp, back to cold engine= 1 duty cycle). BTW this is the way to solve a failed smog test due to the CEL being on. After the needed duty cycles have been completed, unless you have repaired what was wrong, the CEL will come back on.