We bought our 1990 Honda Accord used and it came with no owner's manual. What does the "S" mean on the dashboard warning lights? Does it require service? Presumably an oil change? Thank you!

NO, IT DOES NOT MEAN OIL CHANGE.....THE "S" IS AN INDICATOR LIGHT WHICH INFORMS YOU THAT THE CAR IS IN "SPORT SHIFT" MODE. What that means is that with the light on the computer will raise the shift point to a higher engine RPM. Hit the button on the shift lever and the shift point RPM returns to normal. Also another function of this light is to diagnose possible engine trouble codes. It the S light stays on no matter if the sport shift button is pressed in or out then that means trouble. You can pull the code your self by simply removing the passenger side kick panel and locating the empty two wire plug and use a piece of wire to bridge the two wire terminals. The S light will begin to flash and pause. long flashes equal 10 and short flashes equal 1

Yes it means Service (Oil Change).