It should have the screw that you turn around and then the LED's flash, my ecu has the fault codes written on the ECU case but generally if you get flashing LED's it means something has crapped out or is disconnected
just look up "reading nissan ecu fault codes"
the best site Ive found is one for silvias I think (but same style ECU as the early RB20's)
it will have a screw on it, you turn it till it flashes a certain number of times (I think its 3...but check), then turn the screw back.
then it will start flashing......first the left hand LED.....then the other one.
count the number of times it flashes, and thats your code (the first one flashes once per 10 unit.....ie if it flashes 5 times, thats code 50)
if there is no fault codes, you will get 5 red and 5 green flashes (code 55).
code 55 means all is OK (with the sensors it knows how to test)
so if you get flashing LED's, it does NOT mean it is broken