service light on 2002 Toyota Echo

several months ago, a service light came on. it is on the right side and is yellow. Also, the icon looks like a manifold(?) or the place where one would put oil. I checked fluids, was low on coolant, filled it. I disconnected the battery but a few days later the light came on again. Also, i believe it happened around the time the odometer turned to 60,000 miles (is this why?)

Asked by for the 2002 Toyota Echo
I believe the light you mention sounds like the "Check Engine" light. Does the icon look like a yellow outline of an engine? f the Check Engine Light/Service Engine Soon light illuminates while you are driving, the car's on board computer sees a fault in the engines management system that is causing an excess amount of pollutants to be emitted from your car. This could result in engine damage if left neglected. Some problems that can cause the Check Engine light to stay on may take two "drive cycles' to complete before illuminating the Check Engine Light. The computer sees a problem and looks for an identical set of circumstances to occur to confirm that it has indeed seen a problem before turning on the light. A Check Engine light that continually flashes while you are driving is serious and is a sign that the computer sees a problem that seriously risks damaging the catalytic converter which may result in an expensive repair or even may cause a fire! Diagnostic codes are stored in the vehicle's computer and can be retrieved using a scantool that communicates with the computer in your car. We have in our Repairpal website an encyclopedia with in depth articles about computer, and computer control systems, emission and driveability problems.