Understanding the On-Board Diagnostics II (OBD2) port in your 1997 Honda Civic is crucial for modern vehicle maintenance and troubleshooting. This port is your gateway to accessing your car’s computer, allowing mechanics and DIY enthusiasts to read diagnostic trouble codes (DTCs) and monitor vehicle health. This article provides a detailed look at the 1997 Honda Civic OBD2 port schematics, ensuring you have the information needed for effective diagnostics.
The OBD2 port is a standardized interface, but understanding the pinout and what each pin signifies is essential for using diagnostic tools correctly. Below is a schematic breakdown of the OBD2 port in your 1997 Honda Civic:
| Pin | Signal | Description |
|---|---|---|
| 4 | CGND | Chassis ground |
| 5 | SGND | Signal ground |
| 6 | CAN High | J-2284 |
| 7 | K-LINE | (ISO 9141-2 and ISO/DIS 14230-4) |
| 9 | SCS | SCS (Service Check System) – diagnostic codes |
| 12 | Programming out | |
| 13 or 14? | Input/Output for VTM-4 and immobilizer control | |
| 14 | CAN Low | J-2284 (WEN) |
| 15 | ISO 9141-2 L-LINE | (ISO 9141-2 and ISO/DIS 14230-4) |
| 16 | +12v | Battery power (unswitched) |
Key Pin Descriptions for 1997 Honda Civic OBD2 Port:
- Pin 4 & 5 (Grounds): CGND (Chassis Ground) and SGND (Signal Ground) provide the necessary ground connections for the OBD2 interface to function correctly. These are standard ground pins in most OBD2 implementations.
- Pin 6 & 14 (CAN Bus): CAN High and CAN Low pins are part of the CAN (Controller Area Network) bus, specifically J-2284 protocol. While listed here, it’s important to note that the 1997 Honda Civic primarily uses ISO 9141-2 for diagnostics, and CAN protocol became more prevalent in later models. The inclusion of CAN pins might be for future-proofing or specific advanced diagnostic functions, though likely not the primary protocol for a ’97 Civic.
- Pin 7 (K-Line): The K-Line is crucial for communication based on ISO 9141-2 and ISO/DIS 14230-4 protocols. This is the primary diagnostic communication line for many vehicles of this era, including the 1997 Honda Civic.
- Pin 9 (SCS): SCS (Service Check System) is a Honda-specific pin used for retrieving diagnostic codes, potentially through a different method or protocol than standard OBD2 readers on the K-Line. It’s related to Honda’s proprietary diagnostic system.
- Pin 15 (L-Line): The L-Line is another communication line associated with ISO 9141-2 protocol. Together with the K-Line, it enables bidirectional serial communication for diagnostics.
- Pin 16 (+12V Battery Power): This pin provides direct battery power to the OBD2 diagnostic tool, ensuring it has the necessary power to operate when connected to the vehicle.
To further understand the compatibility of OBD2 protocols with various Honda models, refer to the table below which includes information relevant to the 1997 Honda Civic and surrounding years.
| Model | Engine | Year (starting from) | OBD-2 Protocol |
|---|---|---|---|
| Honda Civic | 1996 | ISO 14230-4, ISO 9141-2 | |
| Honda Civic Del Sol | 1997 | ISO 14230-4, ISO 9141-2 |
This table confirms that the 1997 Honda Civic, along with models from 1996 onwards, is OBD2 compliant and utilizes ISO 14230-4, ISO 9141-2 protocols. This is consistent with the K-Line and L-Line pins highlighted in the schematics.
Understanding diagnostic trouble codes is also vital when working with your 1997 Honda Civic’s OBD2 system. Here are some common Honda specific diagnostic codes:
| Code | Description |
|---|---|
| P1106 | Barometric Pressure Circuit Range/Performance |
| P1107 | Barometric Pressure Circuit Low Input |
| P1108 | Barometric Pressure Circuit High Input |
| P1121 | Throttle Position Lower Than Expected |
| P1122 | Throttle Position Higher Than Expected |
| P1128 | MAP Lower Than Expected |
| P1129 | MAP Higher Than Expected |
| P1149 | Primary HO2S (Sensor 1) Circuit Range/Performance Problem |
| P1162 | Primary HO2S (No. 1) Circuit Malfunction |
| P1163 | Primary HO2S (No. 1) Circuit Slow Response |
| P1164 | Primary HO2S (No. 1) Circuit Range/Performance |
| P1165 | Primary HO2S (No. 1) Circuit Range/Performance |
| P1166 | Primary HO2S (No. 1) Heater System Electrical |
| P1167 | Primary HO2S (No. 1) Heater System |
| P1168 | Primary HO2S (No. 1) LABEL Low Input |
| P1169 | Primary HO2S (No. 1) LABEL High Input |
| P1253 | VTEC System Malfunction |
| P1257 | VTEC System Malfunction |
| P1258 | VTEC System Malfunction |
| P1259 | VTEC System Malfunction |
| P1297 | Electrical Load Detector Circuit Low Input |
| P1298 | Electrical Load Detector Circuit High Input |
| P1300 | Multiple Cylinder Misfire Detected |
| P1336 | CSF Sensor Intermittent Interruption |
| P1337 | CSF Sensor No Signal |
| P1359 | CKP/TDC Sensor Connector Disconnection |
| P1361 | Intermittent Interruption In TDC 1 Sensor Circuit |
| P1362 | No Signal In TDC 1 Sensor Circuit |
| P1366 | Intermittent Interruption In TDC 2 Sensor Circuit |
| P1367 | No Signal In TDC 2 Sensor Circuit |
| P1381 | Cylinder Position Sensor Intermittent Interruption |
| P1382 | Cylinder Position Sensor No Signal |
| P1456 | EVAP Emission Control System Leak Detected (Fuel Tank System) |
| P1457 | EVAP Emission Control System Leak Detected (Control Canister System) |
| P1459 | EVAP Emission Purge Flow Switch Malfunction |
| P1486 | Thermostat Range/Performance Problem |
| P1491 | EGR Valve Lift Insufficient Detected |
| P1498 | EGR Valve Lift Sensor High Voltage |
| P1508 | IAC Valve Circuit Failure |
| P1509 | IAC Valve Circuit Failure |
| P1519 | Idle Air Control Valve Circuit Failure |
| P1607 | ECM/PCM Internal Circuit Failure A |
| P1655 | SEAF/SEFA/TMA/TMB Signal Line Failure |
| P1656 | Automatic Transaxle |
| P1660 | Automatic Transaxle FI Signal A Circuit Failure |
| P1676 | FPTDR Signal Line Failure |
| P1678 | FPTDR Signal Line Failure |
| P1681 | Automatic Transaxle FI Signal A Low Input |
| P1682 | Automatic Transaxle FI Signal A High Input |
| P1686 | Automatic Transaxle FI Signal B Low Input |
| P1687 | Automatic Transaxle FI Signal B High Input |
| P1705 | Automatic Transaxle Concerns |
| P1706 | Automatic Transaxle Concerns |
| P1738 | Automatic Transaxle Concerns |
| P1739 | Automatic Transaxle Concerns |
| P1753 | Automatic Transaxle Concerns |
| P1758 | Automatic Transaxle Concerns |
| P1768 | Automatic Transaxle Concerns |
| P1773 | Automatic Transaxle Concerns |
| P1785 | Automatic Transaxle Concerns |
| P1786 | Automatic Transaxle Concerns |
| P1790 | Automatic Transaxle Concerns |
| P1791 | Automatic Transaxle Concerns |
| P1792 | Automatic Transaxle Concerns |
| P1793 | Automatic Transaxle Concerns |
| P1794 | Automatic Transaxle Concerns |
| P1870 | Automatic Transaxle Concerns |
| P1873 | Automatic Transaxle Concerns |
| P1879 | Automatic Transaxle Concerns |
| P1885 | Automatic Transaxle Concerns |
| P1886 | Automatic Transaxle Concerns |
| P1888 | Automatic Transaxle Concerns |
| P1890 | Automatic Transaxle Concerns |
| P1891 | Automatic Transaxle Concerns |
For those looking to build their own diagnostic cables or understand the wiring, here are some helpful OBD-II cable schematics links:
- OBD-2 ISO 9141-2 (14230-4, KWP2000) simple serial cable
- OBD-2 J1850 PWM, J1850 VPW serial ELM327 cable
- OBD-2 universal ISO 15765-4 CAN, SAE J1850 PWM, SAE J1850 VPW, ISO 9141-2, ISO 14230-4 and SAE J1939 diagnostic cable
In conclusion, this guide to the 1997 Honda Civic OBD2 port schematics aims to provide you with a comprehensive understanding of your vehicle’s diagnostic interface. By knowing the pinouts, supported protocols, and common diagnostic codes, you are better equipped to maintain your vehicle and utilize OBD2 diagnostic tools effectively. Whether you’re a seasoned mechanic or a car owner keen on understanding your vehicle better, this information is a valuable resource for working with your 1997 Honda Civic’s OBD2 system.
