Yes. You have to get to the test mode selector screw on the ECU.
With the ignition switch turned to "On", turn the selector screw fully clockwise, wait 2 seconds, then turn fully counterclockwise. Start engine.
The malfunction indicator lamp will blink a number of times between 1 and 5, then it will pause and blink again a number of times between 1 and 5. There's no single digit codes.