Can adding too much coolant cause the engine light to come on?

may be a co-incidence~ what happens is that fluid expands....that's how there is a COLD and HOT levels on the translucent reservoir tank~ but putting too much in...will percolate out the drip tube and push out the excess till HOT temps are reached...when you park the expansion will turn into contraction...and we can hope will settle down to the line for cold...exactly....what a perfect world...sign me up~

the Check engine may be because 1.) you left your gas cap off 2.) you filled up to the cap rather then stopping at the FIRST CLICK dammit~ 3.) the oxygen sensor is all used up or malfunctioning~ 4.) maintenance schedule says "Now's the time to bring it in for the 30,000 mi checkup could be anything really...sure hope you do not solve it with the famous BLACK TAPE solution...that is bad and will cause MORE pollution!~

Thanks for responding. I checked the gas cap and that wasn't the culprit. I checked the level in the reservoir and it is well above the cold line. Thats why I thought maybe it was that. I have 13% oil life, 36%transmission life and 14.5% battery life. Could be one of those as the culprit too right?

That's transmission fluid life.

please you did not fill it up past the first click...that would have choked the evaporative system and the light would come on~

that's all I got...thank you...for the positive energy you brought me today am giving you one of my 1/288 paintings...gonna make 1000 of them....in time~