Check engine light on 95 E420
 

I put a can of Lubro Moly valve cleaner in a full tank of gas. After driving about 50 miles I shut the car off. When I restarted the car the check engine light came on. I have driven the car 200 miles with the light on. The car is running perfectly. The can says it will not harm catalytic converters or O2 sensors. What happened? Will disconnecting the battery make the light go off?