Computer controls first started showing up in the 1970s, much to the horror of non-factory mechanics. The early days of computer controls were like the Wild West, where every manufacturer used whatever coding system it wanted to. That meant that a mechanic might have to have a dozen expensive computer code readers to conduct business. The pre-OBD-II systems the 1994 Accord used made things a little easier, but not as easy or comprehensive as the later OBD-II protocol.
Prior to enacting OBD-II code protocol in 1995, Honda used the 1980s "blinky light" or "ALDL" method of communicating faults. These systems -- as used by Honda -- don't have an information download port like OBD-II cars do, or even the way some OBD-I cars did. If you look under the glove compartment, you'll see a blue, two-wire plug hanging down. If you turn the ignition key to the "on" position, and use a bent, U-shaped paper clip or piece of wire to jump one plug terminal to the other, the check engine light will begin to flash. The flashes work kind of like Morse code, with the flashes corresponding to a numbered Honda code.
Codes 1 through 9 are signified by the corresponding number of short flashes, followed by a long pause; a Code 8 would be eight short flashes and a long pause. For 10 and over, the tens place is noted by long flashes, and the ones place by short flashes. So, a Code 43 would be four long flashes, followed by three short ones and a pause. A Code 61 would be six long flashes, one short flash and a pause. Check the Resources section below for a full list of Honda OBD-I flash codes.
