Wait a minute. You said "SERVICE LIGHT" not "CHECK ENGINE"light. The service light means you have covered a certain number of miles since your last inspection, and it only means it is time for a inspection at the dealer. On my 1994 850NA, the service light comes on every 5000 miles. Please take a look at your instrument panel. See if there is a little round black rubber about a third of an inch in diameter on the "glass". If you find it take it out. You willsee a black plastic stick behind it, protruding from the instrumant panel.
Press it down carefully using a small screw driver or a toothpick. No need to apply much force. Do it with ignition switch on. The service light will go out, and will come on again at the factory scheduled milleage. These instructions are ggod for one of the two different makes of the instrument panel. Yazaki I believe. The other, VDO is not so easy.
Apparently it was just a coincidence that it came on after you cleaned the flame trap, as a certain milleage was reached. Let us know if that solves you problem.