Honda ECU Codes   Code 1 Accord 85-98 Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Oxgen Sensor "A" (Primary) Defective cicuit or unplugged/defective sensor 2 Accord 85-98 Civic 86-87 CRX 85-87 Del Sol 93-97 Prelude N / A Oxgen Sensor "B" (Primary) Defective cicuit or unplugged/defective sensor 3 Accord 85-98 Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Manifold Absolute Pressure (MAP) Sensor Defective cicuit or unplugged/defective sensor 4 Accord 90-98 Civic 88-98 CRX 88-91 Del Sol 93-97 Prelude 85-98 Crankshaft Position Sensor (CKP) Defective cicuit or unplugged/defective sensor 5 Accord 85-94 96-98 Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Manifold Absolute Pressure (MAP) Sensor Mechanical problem/disconnected pipingb 6 Accord 85-98 Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Engine Coolant Temperature (ECT) Sensor Defective circuit or unplugged/defective sensor Code 7 Accord 85-98 Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Throttle Position (TP) Sensor Defective cicuit or unplugged/defective sensor 8 Accord 85-98 Civic 86-98 CRX 85-87 Del Sol 93-97 Prelude N / A Top Dead Center (TDC) Sensor Defective cicuit or unplugged/defective sensor 9* Accord 85-98** Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Cylinder Position (CYP) Sensor Defective cicuit or unplugged/defective sensor *N/A to any throttle body injection Honda's **N/A to V-6 engines 10 Accord 85-98 Civic 86-98 CRX 88-91 Del Sol 93-97 Prelude 85-98 Intake Air Temperature (IAT) Sensor Defective cicuit or unplugged/defective sensorb 12 Accord 85-98 Civic 86-98* CRX 85-91* Del Sol N / A Prelude 85-98 Exhaust Gas Recirculation (EGR) Lift Sensor Defective circuit or unplugged/defective sensor *N/A if your car is not equipped with an EGR valve Code 13 Accord 85-98 Civic 86-98 CRX 85-91 Del Sol 93-97 Prelude 85-98 Atmospheric Pressure (BARO) Sensor Defective cicuit or unplugged/defective sensor 14 Accord 88-98 Civic 88-98 CRX 88-91 Del Sol 93-97 Prelude 88-98 Idle Air Control (IAC) Valve Defective cicuit or unplugged/defective sensor 15 Accord 90-95 Civic 88-95 CRX 88-91 Del Sol 93-95 Prelude 88-95 Ignition Output Signal Missing or defective ignition output signal 16 Accord 90-95 Civic 88-95 CRX 88-91 Del Sol 93-95 Prelude 88-95 Fuel Injector System Defective cicuit or unplugged/defective fuel injectorb 17 Accord 88-98 Civic 88-98 CRX 88-91 Del Sol 93-97 Prelude 88-98 Vehicle Speed (VSS) Sensor Defective circuit or unplugged/defective sensor 19 Accord N / A Civic 88-95 CRX 88-91 Del Sol 93-97 Prelude N / A Automatic Trans. Lock Up Control Solenoid Valve Defective circuit or unplugged/defective solenoid valve Code 20 Accord 90-98 Civic 88-98 CRX 88-91 Del Sol 93-97 Prelude 92-98 Electrical Load Dectector Defective cicuit or unplugged/defective sensor 21* Accord 94-98** Civic 92-95 CRX N / A Del Sol 93-95 Prelude 93-95 VTec Solenoid Valve Defective cicuit or unplugged/defective solenoid valve *N/A if your car is not a VTec **N/A to V-6 engines 22* Accord 94-98 Civic 92-98 CRX N / A Del Sol 93-97 Prelude 93-98 VTec Oil Pressure Switch Defective cicuit or unplugged/defective oil pressure switch *N/A if your car is not a VTec 23 Accord 98* Civic 96-98 CRX N / A Del Sol 93-97 Prelude 92-98 Knock (KS) Sensor Defective circuit or unplugged/defective sensor *N/A to V-6 engines 30 Accord 90-98 Civic N / A CRX N / A Del Sol N / A Prelude 92-98* Automatic Trans. Signal: "A"/SEAF/SEFA/TMA or TMB Defective circuit or unplugged/defective sensor *Except for 96 Prelude 31 Accord 90-95 Civic N / A CRX N / A Del Sol N / A Prelude 92-95 Automatic Trans. Signal: "B" Defective circuit or unplugged/defective sensor Code 41 Accord 90-98 Civic 92-98 CRX N / A Del Sol 93-97 Prelude 90-98 Primary Oxygen Sensor: Heater Circuit Malfunction 43 Accord 90-95 Civic 92-95 CRX N / A Del Sol 93-95 Prelude 90-95 Fuel Supply System Defective or malfunctioning fuel supply system 45 Accord 96-98 Civic 92-96 CRX N / A Del Sol 93-97 Prelude 96-98 System Too Lean or Too Rich Malfunctioning in the fuel monitoring systems 48 Accord 98 Civic 92-98 CRX N / A Del Sol N / A Prelude N / A Lean Air Fuel (LAF) Sensor Defective circuit or unplugged/defective sensor 54 Accord 96 Civic 96-98 CRX N / A Del Sol 96-97 Prelude N / A Crankshaft Speed Fluctuation (CKF) Sensor Defective circuit or unplugged/defective sensor 58 Accord 98* Civic N / A CRX N / A Del Sol N / A Prelude N / A Top Dead Center (TDC) Sensor 2 Defective circuit or unplugged/defective sensor *V-6 Engine only Code 61 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Oxygen Sensor, Heated: Sensor 1 (Primary) High Voltage, Low Voltage, or Slow Response 63 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Oxygen Sensor, Heated: Sensor 2 (Secondary) High Voltage, Low Voltage, or Slow Response 65 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Oxygen Sensor Heater (Secondary) Malfunctioning or defective oxygen sensor heater 67 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Catalyst System Efficiency Below Threshold Malfunctioning or defective catalyst system 70 Accord 96-98 Civic 96-98 CRX N / A Del Sol N / A Prelude 96-98 Automatic Transmission Malfunctioning of the autmoatic transmission controls 71 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Cylinder 1 Misfire or a Random Misfire Code 72 Accord 96-98 Civic 98 CRX N / A Del Sol 96-97 Prelude 96-98 Cylinder 2 Misfire or a Random Misfire 73 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Cylinder 3 Misfire or a Random Misfire 74 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Cylinder 4 Misfire or a Random Misfire 75 Accord 98* Civic N / A CRX N / A Del Sol N / A Prelude N / A Cylinder 5 Misfire or a Random Misfire *Applies only to V-6 engines 76 Accord 98* Civic N / A CRX N / A Del Sol N / A Prelude N / A Cylinder 6 Misfire or a Random Misfire *Applies only to V-6 engines 80 Accord 96-98 Civic 96-98 CRX N / A Del Sol N / A Prelude 96-98 Exhaust Gas Recirculation Insufficient Flow Detected Code 86 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Engine Coolant Temperature (ECT) Sensor Circuit Range/Performance Problem 90 Accord 97-98 Civic 96-98 CRX N / A Del Sol N / A Prelude 97-98 Evaporative Emission Control System Leakage in the fuel tank area 91 Accord 96-98 Civic 96-98 CRX N / A Del Sol N / A Prelude 97-98 Fuel Tank Pressure Sensor Low Input 92 Accord 96-98 Civic 96-98 CRX N / A Del Sol 96-97 Prelude 96-98 Vaporative Emission Control System Insufficient Purge Flow