changed the oil in the wife's car yesterday, washed it and the engine too. my problem is that i crawled under it to loosen the bolt to change the oil but took off the trans bolt. drained a little less than 2 qts. emptied the engine oil, replaced filter, etc. after that, i cleaned the engine. i knew i needed trans fluid so i backed it out of the drive to a level surface (less than 20 ft) and noticed the gear selector buttons and arrow on the dash were flashing. i assumed that was my warning that the fluid was low. then i noticed the check engine light came on. i've checked everything and cannot find reason for it to be on. is it possible on due to me moving it or is this just coincidence??? to verify if it is just the fluid being low, how can i reset the check engine light???

thanks for the trouble.....