Honda Civic OBD2 Codes: Your Comprehensive Guide to Decoding Error Signals

Navigating the complexities of modern vehicle diagnostics can be daunting, especially when the check engine light illuminates in your Honda Civic. Fortunately, the On-Board Diagnostics II (OBD2) system is designed to help both car owners and mechanics pinpoint potential issues. This guide provides a detailed overview of Honda Civic Obd2 Codes, helping you understand what these codes mean and how to address them.

Understanding OBD2 Systems in Your Honda Civic

The OBD2 system is a standardized system in most cars sold in the United States since 1996, including the Honda Civic. Its primary function is to monitor the performance of your vehicle’s engine and emissions systems. When the system detects a problem, it generates a Diagnostic Trouble Code (DTC), commonly known as an OBD2 code, and illuminates the check engine light on your dashboard.

What is an OBD2 Code?

An OBD2 code is a five-character alphanumeric code that provides a clue about the nature of the problem your vehicle is experiencing. These codes are standardized across the automotive industry, but specific interpretations can vary slightly depending on the manufacturer and model year. For Honda Civic owners, understanding these codes is the first step towards effective vehicle maintenance and repair.

Locating the OBD2 Port in Your Honda Civic

Before you can read any OBD2 codes, you’ll need to locate the diagnostic port in your Honda Civic. Typically, the OBD2 port is located within the driver’s side interior, usually under the dashboard, near the steering column. Refer to your Honda Civic owner’s manual for the precise location if you have trouble finding it.

Using an OBD2 Scanner to Read Codes

To retrieve OBD2 codes, you will need an OBD2 scanner. These scanners range from basic handheld devices to more advanced professional-grade tools.

1. Turn off your Honda Civic’s ignition.
2. Locate the OBD2 port.
3. Plug the OBD2 scanner into the port.
4. Turn the ignition to the “ON” position (do not start the engine).
5. Follow the scanner’s instructions to read the stored codes.

The scanner will display the codes, often with a brief description. It’s important to note down the exact codes for accurate diagnosis.

Comprehensive List of Honda Civic OBD2 Codes

This section provides a comprehensive list of OBD2 codes that may be relevant to your Honda Civic. It’s organized by code ranges to help you navigate and understand potential problem areas. Keep in mind that this list is extensive, and not every code will apply to every Honda Civic model year. Always consult your vehicle’s service manual for the most accurate information.

P0000 – P0099: Fuel and Air Metering and Auxiliary Emission Controls

These codes often relate to issues with the fuel and air mixture, which is crucial for engine performance and emissions control.

• P0010: Variable Valve Timing Control (VTC) Oil Control Solenoid Valve Malfunction

• P0011: Variable Valve Timing Control (VTC) System Malfunction

• P0101: Mass Airflow (MAF) Sensor Range/Performance Problem

• P0102: Mass Airflow (MAF) Sensor Circuit Low Voltage

• P0103: Mass Airflow (MAF) Sensor Circuit High Voltage

• P0106: Manifold Absolute Pressure (MAP) Sensor Range/Performance Problem

• P0107: Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage

• P0108: Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

• P0111: Intake Air Temperature (IAT) Sensor Circuit Range/Performance Problem

• P0112: Intake Air Temperature (IAT) Sensor Circuit Low Voltage

• P0113: Intake Air Temperature (IAT) Sensor Circuit High Voltage

• P0116: Engine Coolant Temperature (ECT) Sensor Circuit Range/Performance Problem

• P0117: Engine Coolant Temperature (ECT) Sensor Circuit Low Input

• P0118: Engine Coolant Temperature (ECT) Sensor Circuit High Input

• P0122: Throttle Position (TP) Sensor Circuit Low Input

• P0123: Throttle Position (TP) Sensor Circuit High Input

• P0125: Engine Coolant Temperature (ECT) Sensor Slow Response

• P0128: Cooling System Malfunction

• P0131: Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Circuit Low Voltage

• P0132: Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Circuit High Voltage

• P0133: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) Circuit Slow Response

• P0134: Air/Fuel Ratio (A/F) Sensor (Sensor 1) No Activity Detected

• P0135: Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Heater Circuit Malfunction

• P0137: Secondary Heated Oxygen Sensor (Secondary HO2S) Circuit Low Voltage

• P0138: Secondary Heated Oxygen Sensor (Secondary HO2S) Circuit High Voltage

• P0139: Secondary Heated Oxygen Sensor (Secondary HO2S) Slow Response

• P0141: Secondary Heated Oxygen Sensor (Secondary HO2S) (Sensor 2) Heater Circuit Malfunction

• P0143: Third Heated Oxygen Sensor (Third HO2S) (Sensor 3) Circuit Low Voltage

• P0144: Third Heated Oxygen Sensor (Third HO2S) (Sensor 3) Circuit High Voltage

• P0145: Third Heated Oxygen Sensor (Third HO2S) (Sensor 3) Circuit Slow Response

• P0147: Third Heated Oxygen Sensor (Third HO2S) (Sensor 3) Heater Circuit Malfunction

• P0153: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) Circuit Slow Response

• P0154: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) Heater System Malfunction

• P0155: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) Heater Circuit Malfunction

• P0157: Front Secondary Heated Oxygen Sensor (Secondary HO2S) (Bank 2, Sensor 2) Circuit Low Voltage

• P0158: Front Secondary Heated Oxygen Sensor (Secondary HO2S) (Bank 2, Sensor 2) Circuit High Voltage

• P0159: Front Secondary Heated Oxygen Sensor (Secondary HO2S) (Bank 2, Sensor 2) Circuit Slow Response

• P0161: Front Secondary Heated Oxygen Sensor (Secondary HO2S) (Bank 2, Sensor 2) Heater Circuit Malfunction

• P0171: Fuel System Too Lean

• P0172: Fuel System Too Rich

• P0174: Front Bank (Bank 2) Fuel System Too Lean

• P0175: Front Bank (Bank 2) Fuel System Too Rich

• P0191: Fuel Pressure Sensor Range/Performance Problem

• P0192: Fuel Pressure Sensor Circuit Low Voltage

• P0193: Fuel Pressure Sensor Circuit High Voltage

• P0196: EOT Sensor/Range Performance Problem

• P0197: EOT Sensor Circuit Low Voltage

• P0198: EOT Sensor Circuit High Voltage

P0200 – P0299: Injector Circuit Malfunctions

Codes in this range typically indicate problems with the fuel injectors or their circuits.

• P0222: Throttle Position (TP) Sensor 2 Circuit Low Voltage
• P0223: Throttle Position (TP) Sensor 2 Circuit High Voltage

P0300 – P0399: Ignition System or Misfire

Misfire codes are common and can indicate various issues from spark plugs to more serious engine problems.

• P0300: Random Misfire
• P0301: No. 1 Cylinder Misfire
• P0302: No. 2 Cylinder Misfire
• P0303: No. 3 Cylinder Misfire
• P0304: No. 4 Cylinder Misfire
• P0305: No. 5 Cylinder Misfire
• P0306: No. 6 Cylinder Misfire
• P0325: Knock Sensor Circuit Malfunction
• P0335: Crankshaft Position (CKP) Sensor Circuit No Signal
• P0336 P0339: Crankshaft Position (CKP) Sensor Circuit Intermittent Interruption
• P0340: Camshaft Position (CMP) Sensor No Signal
• P0341: Camshaft Position (CMP) Sensor A Intermittent Interruption
• P0341: Variable Valve Timing Control (VTC) Phase Gap
• P0344: Camshaft Position (CMP) Sensor Intermittent Interruption
• P0365: Camshaft Position (CMP) Sensor B No Signal
• P0366 P0369: Camshaft Position (CMP) Sensor B Intermittent Interruption
• P0385: Crankshaft Position (CKP) Sensor B No Signal
• P0389: Crankshaft Position (CKP) Sensor B Intermittent Interruption

P0400 – P0499: Auxiliary Emission Controls

These codes are related to systems designed to reduce emissions, such as EGR and EVAP systems.

• P0401: Exhaust Gas Recirculation (EGR) Insufficient Flow

• P0404: Exhaust Gas Recirculation (EGR) Control Circuit Range/Performance Problem

• P0406: Exhaust Gas Recirculation (EGR) Valve Position Sensor Circuit High Voltage

• P0410: Air Pump Circuit Malfunction

• P0411: Secondary Air Injection System Incorrect Flow

• P0420: Catalyst System Efficiency Below Threshold

• P0430: Front Bank Catalyst System Efficiency Below Threshold (Bank 2)

• P0441: Evaporative Emission (EVAP) Control System Incorrect Purge Flow

• P0442: Evaporative Emission (EVAP) System Small Leak Detected

• P0443: Evaporative Emission (EVAP) Canister Purge Valve Circuit Malfunction

• P0451: Fuel Tank Pressure (FTP) Sensor Range/Performance Problem

• P0452: Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

• P0453: Fuel Tank Pressure (FTP) Sensor Circuit High Voltage

• P0456: Evaporative Emission (EVAP) System Very Small Leak Detected

• P0457: Evaporative Emission (EVAP) System Leak Detected Fuel Fill Cap Loose/Off

• P0461: Fuel Gauge Sending Unit Range/Performance Problem

• P0462: Fuel Gauge Sending Unit Circuit Low Voltage

• P0463: Fuel Gauge Sending Unit Circuit High Voltage

• P0496: Evaporative Emission (EVAP) System High Purge Flow

• P0497: Evaporative Emission (EVAP) System Low Purge Flow

• P0498: Evaporative Emission (EVAP) Canister Vent Shut Valve Control Circuit Low Voltage

• P0499: Evaporative Emission (EVAP) Canister Vent Shut Valve Control Circuit High Voltage

P0500 – P0599: Vehicle Speed, Idle Control, and Auxiliary Inputs

This range includes codes related to vehicle speed, idle control systems, and various sensor inputs.

• P0500: Vehicle Speed Sensor (VSS) Circuit Malfunction
• P0501: Vehicle Speed Sensor (VSS) Range/Peformance Problem
• P0505: Idle Control System Malfunction
• P0506: Idle Control System RPM Lower Than Expected
• P0507: Idle Control System RPM Higher Than Expected
• P0511: Idle Air Control (IAC) Valve Circuit Malfunction
• P0521: EOP Sensor Range/Performance Problem
• P0522: EOP Sensor Circuit Low Voltage
• P0523: EOP Sensor Circuit High Voltage
• P0560: ECM Back-up Circuit Low Voltage
• P0563: Engine Control Module (ECM)/Powertrain Control Module (PCM) Power Source Circuit Unexpected Voltage

P0600 – P0699: Computer Output Circuit Checks

These codes often indicate problems within the vehicle’s computer systems (ECM/PCM).

• P0600: Multiplex Control System Troubleshooting
• P0603: ECM/PCM Internal Control Module Keep Alive Memory (KAM) Error
• P0606: ECM/PCM Processor Malfunction
• P0661: Intake Manifold Runner Control (IMRC) Valve Position Sensor Circuit Low Voltage
• P0662: Intake Manifold Runner Control (IMRC) Valve Position Sensor Circuit High Voltage
• P0685: ECM/PCM Power Relay Control Circuit Malfunction

P0700 – P0999: Transmission

Codes in this range are specific to the automatic transmission system in Honda Civics equipped with one.

• P0700: Automatic Transmission Control System
• P0705: Short in Transmission Range Switch Circuit (Multiple Shift-position Input)
• P0706: Open in Transmission Range Switch Circuit
• P0710 P0711: Problem in ATF Temperature Sensor Circuit
• P0712: Short in ATF Temperature Sensor Circuit
• P0713: Open in ATF Temperature Sensor Circuit
• P0715 P0716: Problem in Mainshaft Speed Sensor Circuit
• P0717: Problem in Mainshaft Speed Sensor Circuit (No Signal Input)
• P0718: Mainshaft Speed Sensor Intermittent Failure
• P0720: Countershaft Speed Sensor Circuit Malfunction
• P0720 P0721: Problem in Countershaft Speed Sensor Circuit
• P0722: Problem in Countershaft Speed Sensor Circuit (No Signal Input)
• P0723: Countershaft Speed Sensor Intermittent Failure
• P0725: Engine Speed Input Circuit Malfunction
• P0730: Problem in Shift Control System
• P0731: Problem in 1st Clutch and 1st Clutch Hydraulic Circuit
• P0732: Problem in 2nd Clutch and 2nd Clutch Hydraulic Circuit
• P0733: Problem in 3rd Clutch and 3rd Clutch Hydraulic Circuit
• P0734: Problem in 4th Clutch and 4th Clutch Hydraulic Clutch
• P0735: Problem in 5th Clutch and 5th Clutch Hydraulic Circuit
• P0740: Problem in Lock-up Control System
• P0741: Torque Converter Clutch Hydraulic Clutch Stuck OFF
• P0743: Problem in Torque Converter Clutch Solenoid Valve Circuit
• P0745: Problem in Hydraulic Control System of A/T Clutch Pressure Control Solenoid Valve A Circuit
• P0746: A/T Clutch Pressure Control Solenoid Valve A Stuck OFF
• P0747: A/T Clutch Pressure Control Solenoid Valve A Stuck ON
• P0748: Problem in A/T Clutch Pressure Control Solenoid Valve A Circuit
• P0750: Problem in Hydraulic Control System of Shift Solenoid Valve A Circuit
• P0751: Shift Solenoid Valve A Stuck OFF
• P0752: Shift Solenoid Valve A Stuck ON
• P0753: Problem in Shift Solenoid Valve A Circuit
• P0756: Shift Solenoid Valve B Stuck OFF
• P0757: Shift Solenoid Valve B Stuck ON
• P0758: Problem in Shift Solenoid Valve B Circuit
• P0761: Shift Solenoid Valve C Stuck OFF
• P0762: Shift Solenoid Valve C Stuck ON
• P0763: Problem in Shift Solenoid Valve C Circuit
• P0771: Shift Solenoid Valve E Stuck OFF
• P0773: Problem in Shift Solenoid Valve E Circuit
• P0775: Problem in the Hydraulic Control System of A/T Clutch Pressure Control Solenoid Valve B Circuit
• P0776: A/T Clutch Pressure Control Solenoid Valve B Stuck OFF
• P0777: A/T Clutch Pressure Control Solenoid Valve B Stuck ON
• P0778: Problem in A/T Clutch Pressure Control Solenoid Valve B Circuit
• P0780: Problem in Shift Control System
• P0795: Problem in Hydraulic Control System of A/T Clutch Pressure Control Solenoid Valve C Circuit
• P0796: A/T Clutch Pressure Control Solenoid Valve C Stuck OFF
• P0797: A/T Clutch Pressure Control Solenoid Valve C Stuck ON
• P0798: Problem in A/T Clutch Pressure Control Solenoid Valve C Ciruit
• P0812: Open in Transmission Range Switch ATP RVS Switch Circuit
• P0842: Short in 2nd Clutch Transmission Fluid Pressure Switch Clutch, or 2nd Clutch Transmission Fluid Pressure Switch (Clutch) Stuck ON
• P0843: Open in 2nd Clutch Transmission Fluid Pressure Switch Circuit, or 2nd Clutch Transmission Fluid Pressure Switch Stuck OFF
• P0845: Problem in 3rd Clutch Pressure Switch Circuit
• P0847: Short in 3rd Clutch Transmission Fluid Pressure Switch Circuit, or 3rd Clutch Transmission Fluid Pressure Switch Stuck ON
• P0848: Open in 3rd Clutch Transmission Fluid Pressure Switch Circuit, or 3rd Clutch Transmission Fluid Pressure Switch Stuck OFF
• P0872: Short in 4th Clutch Transmission Fluid Pressure Switch Circuit, or 4th Clutch Transmission Fluid Pressure Switch Stuck ON
• P0873: Open in 4th Clutch Transmission Fluid Pressure Switch Circuit, or 4th Clutch Transmission Fluid Pressure Switch Stuck OFF
• P0962: Problem in A/T Clutch Pressure Control Solenoid Valve A Circuit
• P0963: Problem in A/T Clutch Pressure Control Solenoid Valve A
• P0966: Problem in A/T Clutch Pressure Control Solenoid Valve B Circuit
• P0967: Problem in A/T Clutch Pressure Control Solenoid Valve B
• P0970: Problem in A/T Clutch Pressure Control Solenoid Valve C Circuit
• P0971: Problem in A/T Clutch Pressure Control Solenoid Valve C
• P0973: Short in Shift Solenoid Valve A Circuit
• P0974: Open in Shift Solenoid Valve A Circuit
• P0976: Short in Shift Solenoid Valve B Circuit
• P0977: Open in Shift Solenoid Valve B Circuit
• P0979: Short in Shift Solenoid Valve C Circuit
• P0980: Open in Shift Solenoid Valve C Circuit
• P0982: Short in Shift Solenoid Valve D Circuit
• P0983: Open in Shift Solenoid Valve D Circuit
• P0985: Short in Shift Solenoid Valve E Circuit
• P0986: Open in Shift Solenoid Valve E Circuit

P1000 – P1999: Manufacturer Specific Codes & System Specific Codes

This range often includes codes that are specific to Honda and may not be standardized across all manufacturers.

• P1020: Valve Pause System Stuck Off
• P1021: Valve Pause System Stuck On
• P1025: Valve Pause System Sticking Off
• P1026: Valve Pause System Sticking On
• P1077: Intake Manifold Runner Control (IMRC) System Malfunction (Low rpm)
• P1078: Intake Mainfold Runner Control (IMRC) System Malfunction (High rpm)
• P1106: Barometric Pressure (BARO) Sensor Circuit Range/Performance Problem
• P1107: Barometric Pressure (BARO) Sensor Circuit Low Voltage
• P1108: Barometric Pressure (BARO) Sensor Circuit High Voltage
• P1121: Throttle Position (TP) Sensor Lower Than Expected
• P1122: Throttle Position (TP) Sensor Higher Than Expected
• P1128: Manifold Absolute Pressure (MAP) Sensor Circuit Lower Than Expected
• P1129: Manifold Absolute Pressure (MAP) Sensor Circuit Higher Than Expected
• P1130: Demand for Changing Both Secondary Heated Oxygen Sensor (Secondary HO2S) (Sensor 2) and Third Heated Oxygen Sensor (Third HO2S) (Sensor 3)
• P1149: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem
• P1149: Air/Fuel Ratio Sensor (Sensor 1) Circuit Lean Range
• P1157: Air/Fuel Ratio (A/F) Sensor (Sensor 1) AFS Line High Voltage
• P1157: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Circuit High Voltage
• P1157: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem
• P1158: Air/Fuel Ratio (A/F) Sensor (Sensor 1) AFS- Terminal Low Voltage
• P1159: Air/Fuel Ratio (A/F) Sensor (Sensor 1) AFS+ Terminal Low Voltage
• P1162: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Slow Response
• P1163: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Slow Response
• P1163: Air/Fuel Ratio Sensor (Sensor 1) Slow Response
• P1164: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem
• P1164: Air/Fuel Ratio (AF) Sensor (Sensor 1) Circuit Range/Performance
• P1165: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem
• P1165: Air/Fuel Ratio Sensor (Sensor 1) Circuit Range/Performance
• P1166: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Heater System Electrical Problem
• P1166: Heated Oxgen Sensor Sensor1 (Primary HO2S) Heater Circuit Malfunction
• P1167: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Heater System Malfunction
• P1167: Heated Oxygen Sensor Sensor1 (Primary LAF HO2S) Heater System Malfunction
• P1168: Air/Fuel Ratio (A/F) Sensor (Sensor 1) LABEL Low Voltage
• P1169: Air/Fuel Ratio (A/F) Sensor (Sensor 1) LABEL High Voltage
• P1182: Fuel Temperature Sensor Circuit Low Voltage
• P1183: Fuel Temperature Sensor Circuit High Voltage
• P1253 P1259: VTEC System Malfunction
• P1297: Electric Load Detector (ELD) Circuit Low Voltage
• P1298: Electric Load Detector (ELD) Circuit High Voltage
• P1300: Random Misfire
• P1324: Knock Sensor Power Source Circuit Low Voltage
• P1336: Engine Speed (RPM) Fluctuation Sensor Intermittent Interruption
• P1337: Engine Speed (RPM) Fluctuation Sensor No Signal
• P1355: Front Ignition Coil Power Circuit Malfunction
• P1359: Crankshaft Position (CKP)/Top Dead Center (TDC) Sensor Circuit Malfunction
• P1361: Camshaft Position (CMP) Sensor A (Top Dead Center (TDC) Sensor) Intermittent Interruption
• P1361: Top Dead Center (TDC) Sensor Intermittent Interruption
• P1362: Camshaft Position (CMP) Sensor A (Top Dead Center (TDC) Sensor) No Signal
• P1362: Top Dead Center (TDC) Sensor No Signal
• P1366: Camshaft Position (CMP) Sensor B (Top Dead Center (TDC) Sensor) Intermittent Interruption
• P1366: Top Dead Center (TDC) Sensor 2 Intermittent Interruption
• P1367: Camshaft Position (CMP) Sensor B (Top Dead Center (TDC) Sensor) No Signal
• P1367: Top Dear Center (TDC) Sensor 2 No Signal
• P1381: Cylinder Position (CYP) Sensor Intermittent Interruption
• P1382: Cylinder Position (CYP) Sensor No Signal
• P1410: Air Pump Malfunction
• P1415: Air Pump Electric Current Sensor Circuit Low Voltage
• P1416: Air Pump Electric Current Sensor Circuit High Voltage
• P1420: Nox Adsorptive Catalyst System Efficiency Below Threshold
• P1438: Motor Drive Module (MDM) Overheating Signal Circuit
• P1438: Motor Drive Module (MDM) Overheating
• P1439: Motor Drive Module (MDM) Short Circuit Sensor Problem
• P1439: Motor Drive Module (MDM) Short Circuit
• P1440: IMA System Problem
• P1445: Bypass Control Problem
• P1448 P1449: Battery Module Overheating
• P1449: Battery Cell Overheating
• P1449: Battery Module Individual Voltage Input Deviation
• P1449: Battery Module Deterioration
• P1449: Battery Module Deviation
• P1454: Fuel Tank Pressure (FTP) Sensor Range/Performance Problem
• P1456: Evaporative Emissions (EVAP) Control System Leakage (Fuel Tank System)
• P1457: Evaporative Emissions (EVAP) Control System Leakage (EVAP Canister System)
• P1459: Evaporative Emission (EVAP) Purge Flow Switch Malfunction
• P1491: Exhaust Gas Recirculation (EGR) Valve Insufficient Lift
• P1486: Cooling System Malfunction
• P1491: Exhaust Gas Recirculation (EGR) Valve Insufficient Lift
• P1498: Exhaust Gas Recirculation (EGR) Valve Position Sensor Circuit High Voltage
• P1505: Positive Crankcase Ventilation (PCV) Air Leakage
• P1508 P1519: Idle Air Control Valve (IACV) Circuit Malfunction
• P1509: Idle Air Control Valve (IACV) Circuit Failure
• P1522: Brake Booster Pressure Sensor Circuit Low Voltage
• P1523: Brake Booster Pressure Sensor Circuit High Voltage
• P1524: Brake Booster Pressure Sensor Range/Performance Problem
• P1541: Climate Control Unit Signal Circuit Low Voltage
• P1542: Climate Control Unit Signal Circuit High Voltage
• P1565: Motor Commutation Signal Problem
• P1568: Battery Module Individual Voltage Input Problem
• P1568: Battery Module Temperature Signal Circuit Problem
• P1568: Battery Cell Temperature Signal Circuit Problem
• P1572: Motor Drive Module (MDM) Temperature Signal Circuit Low Input
• P1572: Motor Drive Module (MDM) Temperature Signal Circuit High Input
• P1576: Motor Drive Module (MDM) Voltge Signal Circuit Low Input
• P1577: High Voltage Detection Signal Circuit Problem
• P1580: Battery Current Circuit Problem
• P1581: Motor Power Inverter (MPI) Module Current Signal Circuit Low Input
• P1581: Motor Power Inverter (MPI) Module Current Signal Circuit High Input
• P1581: Motor Power Inverter (MPI) Module Current Signal Circuit Problem
• P1582: Motor Current U Phase Signal Circuit Low Input
• P1582: Motor Current U Phase Signal Circuit High Input
• P1583: Motor Current V Phase Signal Circuit Low Input
• P1583: Motor Current V Phase Signal Circuit High Input
• P1584: Motor Current W Phase Signal Circuit Low Input
• P1584: Motor Current W Phase Signal Circuit High Input
• P1585: Motor Current Signal Circuit Problem
• P1586: Motor Power Inverter (MPI) Module Current Signal/Battery Current Signal Circuit Problem
• P1607: Engine Control Module (ECM)/Powertrain Control Module (PCM) Internal Circuit Malfunction
• P1630: Transmission Control Module
• P1635: Battery Condition Monitor (BCM) Module Proble
• P1639: MOTB Signal Circuit Malfunction
• P1640: ACTTRQ Motor Torque Signal Circuit Low Input
• P1641: ACTTRQ Motor Torque Signal Circuit High Input
• P1642: QBATT Battery Signal Circuit Low Input
• P1643: QBATT Battery Signal Circuit High Input
• P1644: MOTFSA Signal Malfunction
• P1645: MOTFSB Signal Malfunction
• P1646: MOTSTB Signal Malfunction
• P1647: Power Command Signal Circuit Low Input
• P1647: Power Command Signal Circuit High Input
• P1647: Engine Torque Signal Circuit Low Input
• P1647: Engine Torque Signal Circuit High Input
• P1647: Mode Signal Circuit 1 Low Input
• P1647: Mode Signal Circuit 1 High Input
• P1647: Mode Signal Circuit 2 Problem
• P1647: Engine Speed Signal Circuit Problem
• P1648: Battery Condition Monitor (BCM) Module Communication Signal Circuit Problem
• P1648: Motor Control Module (MCM) Communication Signal Circuit Problem
• P1655: CVT-FI TMA/TMB Signal Line Failure
• P1656: Problem in PCM-toVTM-4 Control Unit Communications Circuit
• P1660: A/T-FI Data Line Failure/TCM – ECM Halt
• P1676 P1678: FPTDR Signal Line Failure
• P1679: RSCD Signal Circuit Malfunction
• P1681: A/T FI Signal A Cicuit Low Voltage
• P1682: A/T FI Signal A Circuit High Voltage
• P1683: Throttle Valve Default Position Spring Performance Problem
• P1684: Throttle Valve Return Spring Performance Problem
• P1686: A/T FI Signal B Circuit Low Voltage
• P1687: A/T FI Signal B Circuit High Voltage
• P1705: Short in Transmission Range Switch Circuit (More than one range position is on at the same time)
• P1706: Open in Transmission Range Switch Circuit
• P1709: Problem Transmission Gear Selection Switch Circuit
• P1730: Problem in Shift Control System: Shift Solenoid Valve A and D Stuck OFF Shift Solenoid Valve B Stuck ON Shift Valves A, B, and D Stuck
• P1731: Problem in Shift Control System: Shift Solenoid Valve E Stuck ON Shift Valve E Stuck A/T Clutch Pressure Control Solenoid Valve A Stuck OFF
• P1732: Problem in Shift Control System: Shift Solenoid Valve B and C Stuck ON Shift Valves B and C Stuck
• P1733: Problem in Shift Control System: Shift Solenoid Valve D Stuck ON Shift Valve D Stuck A/T Clutch Pressure Control Solenoid Valve C Stuck OFF
• P1734: Problem in Shift Control System: Shift Solenoid Valves B and C Stuck ON Shift Valves B and C Stuck
• P1738: Problem in 2nd Clutch Pressure Switch Circuit
• P1739: Problem in 3rd Clutch Pressure Switch Circuit
• P1740: Problem in 4th Clutch Pressure Switch Circuit
• P1750: Mechanical Problem in Hydraulic Control System of A/T Clutch Pressure Control Solenoid Valve Assemblies A and B, or Problem in the Hydraulic Control System
• P1751: Mechanical Problem in Hydraulic Control System of Shift Solenoid Valve B and A/T Clutch Pressure Control Solenoid Valves A and B, or Problem in the Hydraulic Control System
• P1753: Problem in Torque Converter Clutch Solenoid Valve Circuit
• P1751 P1768: Problem in Torque Converter Clutch Solenoid Valve B Circuit
• P1773: Problem in A/T Clutch Pressure Control Solenoid Valve B Circuit
• P1790: Throttle Position (TP) Sensor Circuit Malfunction
• P1791: Vehicle Speed Sensor (VSS) Range/Performance Problem
• P1792: Problem in Engine Coolant Temperature (ECT) Sensor Circuit
• P1793: Manifold Absolute Pressure Sensor Circuit
• P1870: Problem in CVT Speed Change Control Valve Assembly Circuit
• P1873: Problem in CVT Pulley Pressure Control Valve Assembly Circuit
• P1879: Problem in CVT Start Clutch Pressure Control Valve Assembly Circuit
• P1882: Problem in Inhibitor Solenoid Circuit
• P1884: Secondary Gear Speed Sensor 2 Circuit Malfunction
• P1885: CVT Drive Pulley Speed Sensor Circuit
• P1886: CVT Driven Pulley Speed Sensor Circuit
• P1888: CVT Speed Sensor
• P1889: Problem in CVT Speed Sensor 2 Circuit
• P1890: Shift Control System
• P1891: Problem in Start Clutch System
• P1894: CVT Speed Change Control Valve Circuit
• P1895: CVT Pulley Pressure Control Valve Circuit

P2000 – P2999: Powertrain Codes – Specific Systems

This range includes more specific powertrain-related codes.

• P2101: Throttle Actuator System Malfunction
• P2108: Throttle Actuator Control Module Problem
• P2118: Throttle Actuator Current Range/Performance Problem
• P2122: Accelerator Pedal Position (APP) Sensor 1 (Throttle Position Sensor D) Circuit Low Voltage
• P2123: Accelerator Pedal Position (APP) Sensor 1 (Throttle Position Sensor D) Circuit High Voltage
• P2127: Accelerator Pedal Position (APP) Sensor 2 (Throttle Position Sensor E) Circuit Low Voltage
• P2128: Accelerator Pedal Position (APP) Sensor 2 (Throttle Position Sensor E) Circuit High Voltage
• P2135: Throttle Position (TP) Sensor 1/2 Incorrect Voltage Correlation
• P2138: Accelerator Pedal Position (APP) Sensor 1/2 (Throttle Position Sensor D/E) Incorrect Voltage Correlation
• P2176: Throttle Actuator Control System Idle Position Not Learned
• P2195: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Signal Stuck Lean
• P2197: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) Signal Stuck Lean
• P2227: Barometric Pressure (BARO) Sensor Circuit Range/Performance Problem
• P2228: Barometric Pressure (BARO) Sensor Circuit Low Voltage
• P2229: Barometric Pressure (BARO) Sensor Circuit High Voltage
• P2237: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) IP Line High Voltage
• P2238: Air/Fuel Ratio (A/F) Sensor (Sensor 1) AFS+ Line Low Voltage
• P2238: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) IP Line Low Voltage
• P2240: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) IP Line High Voltage
• P2241: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) IP Line Low Voltage
• P2243: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) VCENT Line High Voltage
• P2245: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) VCENT Line Low Voltage
• P2247: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) VCENT Line High Voltage
• P2249: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) VCENT Line Low Voltage
• P2251: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) VS Line High Voltage
• P2252: Air/Fuel Ratio (A/F) Sensor (Sensor 1) AFS- Line Low Voltage
• P2254: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) VS Line High Voltage
• P2255: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) VS Line Low Voltage
• P2279: Intake Air System Leak
• P2413: Exhaust Gas Recirculation (EGR) System Range/Performance Problem
• P2422: Evaporative Emission (EVAP) System Vent Shut Valve Close Malfunction
• P2552: Throttle Actuator Control Module Relay Malfunction
• P2627: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) LABEL Circuit Low Voltage
• P2628: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) LABEL Circuit High Voltage
• P2630: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) LABEL Circuit Low Voltage
• P2631: Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) LABEL Circuit High Voltage
• P2646: VTEC Oil Pressure Switch Circuit Low Voltage
• P2647: VTEC Oil Pressure Switch Circuit High Voltage
• P2648: VTEC Solenoid Valve Circuit Low Voltage
• P2649: VTEC Solenoid Valve Circuit High Voltage
• P2769: Short in Torque Converter Clutch Solenoid Valve Circuit
• P2770: Open in Torque Converter Clutch Solenoid Valve Circuit
• P2A00: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Range/Performance Problem
• P2A03: Front A/F Sensor Circuit (Bank 2, Sensor 1) Circuit Range/Performance Problem

U0000 – U0999: Network Communication

“U” codes indicate communication issues within the vehicle’s network.

• U0073: FCAN Malfunction (Bus-off)
• U0107: Lost Communication With Throttle Actuator Control Module
• U0121: FCAN Malfunction (TCS-PCM)
• U0155: FCAN Malfunction (Gauge Control Module-ECM/PCM)

Troubleshooting Common Honda Civic OBD2 Codes

While the list above is comprehensive, some OBD2 codes are more frequently encountered in Honda Civics than others. Here’s a brief look at some common culprits and their potential solutions:

• P0420 (Catalyst System Efficiency Below Threshold): Often related to a failing catalytic converter or issues with oxygen sensors. Check for exhaust leaks and sensor functionality before replacing the catalytic converter.
• P0171 (Fuel System Too Lean): Can be caused by vacuum leaks, a faulty MAF sensor, a clogged fuel filter, or a weak fuel pump. Inspect for leaks and test sensors.
• P0300 – P0304 (Random/Cylinder Misfire): Spark plugs, ignition coils, fuel injectors, vacuum leaks, and low compression can all cause misfires. Start with basic checks like spark plugs and coils.
• P0401 (EGR Insufficient Flow): A clogged EGR valve or passages are common causes. Cleaning or replacing the EGR valve may be necessary.
• P0135, P0141 (Oxygen Sensor Heater Circuit Malfunction): Often indicates a failing oxygen sensor. Replacing the sensor is usually the solution.

When to Consult a Professional Mechanic

While understanding OBD2 codes and performing basic troubleshooting can be helpful, it’s crucial to know when to seek professional help.

• Unfamiliar Codes: If you encounter codes you don’t understand or are uncomfortable diagnosing.
• Complex Issues: If you suspect a serious mechanical or electrical problem.
• Persistent Codes: If you clear codes and they quickly reappear.
• Multiple Codes: When multiple codes are present, indicating potentially interconnected issues.
• Lack of Tools/Experience: If you don’t have the necessary tools or experience to perform repairs.

A certified mechanic can accurately diagnose the root cause of the OBD2 codes and perform the necessary repairs to ensure your Honda Civic is running safely and efficiently.

Conclusion

Understanding Honda Civic OBD2 codes is a valuable skill for any car owner. By using this guide, you can gain insights into potential issues with your vehicle and take informed steps towards diagnosis and repair. Remember that this list is a starting point, and professional diagnosis is always recommended for complex or persistent problems. Regular maintenance and prompt attention to warning lights will help keep your Honda Civic running smoothly for years to come.