LED display Symptom - Possible Cause for 1985 through 1987 Honda Vehicles
Note: OOOO all 4 lamps on, XXXX all 4 lamps off
OOOO Engine will not start - Check for disconnected control unit ground connector. Also check for a loose connection at the ECU main relay resistor. Possible faulty ECU.
OOOO Engine will not start - Check for a short circuit in the combination meter or warning light wire. Also check for a disconnected control unit ground wire. Possible faulty ECU.
OOOX System does not operate - Faulty ECU
OOXO System does not operate - Faulty ECU
OOXX Fuel-fouled spark plugs, engine stalls frequently - Check for a disconnected MAP sensor coupler or an open circuit in the MAP sensor wire. Also faulty MAP sensor.
OXOO...