1995 S320 Check Engine Light w/o OBDII Plug
 

I own a 1995 S-320 that Does have the OBDII plug under the dash. I have an SRS light that comes on, goes off in a couple of minutes and stays off, this happens every time I start the car. Per another forum I got some contact cleaner and lube from Radio Shack and sprayed into each buckle, no change. My OBDII reader gives me no SRS codes, must be a MB tool only.

I also have developed a check engine light that stays on and the engine runs ok. Last summer I replaced both O2 sensors. I can drive around town for months and the Check Engine light will never come on. If I go on a trip for a couple of hours, no light. When i restart the engine to return, shortly the light goes on and stays on. The code I get is P1137 which an MB tech on the forum says its the downstream, I think that is the rear, O2 sensor. I erased the code to see if it will come on again and will inspect under the car to make sure I tightened the sensor and plug.

All and any suggestions welcome.

Thanks, Steve