Understanding your Honda Civic’s On-Board Diagnostics II (OBD2) Engine Control Unit (ECU) pinouts is crucial for diagnostics, repairs, and performance tuning. This guide provides detailed pinout diagrams for both OBD2A and OBD2B ECUs found in Honda Civic, Del Sol, and Integra models. Whether you are troubleshooting electrical issues or upgrading your engine management system, having the correct pinout information is essential.
OBD2A ECU Pinouts (1996-1998 Honda Civic, Del Sol, Integra)
The OBD2A ECU system was used in Honda vehicles manufactured between 1996 and 1998. This section breaks down the pin assignments for each connector on the OBD2A ECU.
Connector “A” Pinouts
Connector “A” on the OBD2A ECU manages a variety of functions, including injector control, oxygen sensor heater control, and various solenoid valves.
| Pin | Function | Wire Color |
|---|---|---|
| 1 | Injector 4 | Yellow |
| 2 | Injector 3 | Blue |
| 3 | Injector 2 | Blue |
| 4 | Injector 1 | Brown |
| 5 | S02SHTC – (Secondary O2 Sensor Heater Control) | Black/White |
| 6 | P02SHTC – (Primary O2 Sensor Heater Control) | Black/White |
| 7 | ESOL E-EGR – (EGR Control Solenoid Valve) Civic ONLY | ? |
| 8 | VTS – VTEC Solenoid | Green/Yellow |
| 9 | LG1 – (Logic Ground) | Brown/Black |
| 10 | PG1 – (Power Ground) | Black |
| 11 | IGP1 – Power Source | Yellow/Black |
| 12 | IACV – (Idle Air Control Valve) | Black/Blue |
| 15 | PCS – (Evap Purge Control Solenoid Valve) | Red |
| 16 | FLR – (Fuel Pump Relay) (Civic) | Green/Yellow |
| 16 | FLR – (Fuel Pump Relay) (Integra) | Green/Blue |
| 17 | ACC – (A/C Controller) | Black/Red |
| 18 | MIL – (Malfunction Indicator Light) | Green/Orange |
| 19 | ALTC – (Alternator Control) | White/Green |
| 20 | ICM – (Ignition Control Module) | Yellow/Green |
| 22 | LG2 – (Logic Ground) | Brown/Black |
| 23 | PG2 – (Power Ground) | Black |
| 24 | IGP2 – (Power Source) | Yellow/Black |
| 27 | FANC – (Radiator Fan Control) | Green |
| 28 | 2WBS – (Evap Bypass Solenoid Valve) | Blue |
| 29 | VSV – (Evap Control Canister Vent Shut Valve) (Civic) | Light Green/White |
| 29 | VSV – (Evap Control Canister Vent Shut Valve) (Integra) | Light Green |
| 30 | SLU – (Brake Lock) A/T Civic ONLY | White/Red |
| 31 | Empty Slot | |
| 32 | Empty Slot |
Connector “C” Pinouts
Connector “C” is responsible for sensor inputs such as crankshaft and camshaft position sensors, as well as signals for the service check system and OBD2 scan tool.
| Pin | Function | Wire Color (Civic) | Wire Color (Integra) |
|---|---|---|---|
| 1 | CKF P – (CKF Sensor P-side) | Blue/Red | Blue/Red |
| 2 | CKF P – (CKF Sensor P-side) | Blue | Blue |
| 3 | TDC P – (TDC Sensor P-side) | Green | Green |
| 4 | CYP P – (CYP Sensor P-side) | Yellow | Yellow |
| 5 | ACS – (A/C Switch Signal) | Blue/Red | Blue/Red |
| 6 | STS – (Starter Signal Switch) | Blue/Orange | Blue/White |
| 7 | SCS – (Service Check Signal) | Brown | Brown/White |
| 8 | K-Line – (OBD2 Scan Tool Signal) | Black | Green/White |
| 9 | TMA/FAS – (A/T TCM related) | Grey | Yellow |
| 10 | VBU – (Voltage Backup) | White/Blue | White/Blue |
| 11 | CKF M – (CYP Ground) | White/Red | White/Red |
| 12 | CKP M – (CKP Ground) | White | Blue/Yellow |
| 13 | TDC M – (TDC Ground) | Red | White/Blue |
| 14 | CYP M – (CYP Ground) | Black | White |
| 15 | VTM – (VTEC Pressure Switch) | Blue/Black | Blue/Black |
| 16 | PSPSW – (Power Steering Switch Signal) | Green | Green |
| 17 | ALTF – (Alternator FR Signal) | White/Red | White/Red |
| 18 | VSS – (Vehicle Speed Sensor) | Blue/White | Orange |
| 19 | AT CHK – (Detects TCM Signal) Integra ONLY | Blue | |
| 20 | Empty Slot | ||
| 21 | BARO OUT – (Barometric Sensor Output) Integra ONLY | Light Green | Light Green |
| 22 | Empty Slot | ||
| 23 | IP+ (HO2S Pump Cell) Civic ONLY | Black | |
| 24 | IP VS – (HO2S Common) Civic ONLY | Red | |
| 25 | VS+ – (VS Cell Voltage) Civic ONLY | White | |
| 26 | Empty Slot | ||
| 27 | AFSA – (A/T TCM Related) Integra ONLY | Grey | Grey |
| 28 | AFSA – (A/T TCM Related) Integra ONLY | Green/Blue | Green/Blue |
| 29 | ATP/NP/CLSW A/T Park + Neutral or Clutch Switch | Green | Green |
| 29 | ATP/NP/CLSW A/T Park + Neutral or Clutch Switch (M/T Civic) | Red | |
| 30 | TMB – (A/T Related to TCM) Civic ONLY | Pink | |
| 31 | Empty Slot |
Connector “D” Pinouts
Connector “D” is dedicated to various sensors, including throttle position, coolant temperature, manifold absolute pressure, and knock sensors.
| Pin | Function | Wire Color (Civic) | Wire Color (Integra) |
|---|---|---|---|
| 1 | TPS – (Throttle Position Sensor) | Red/Black | Red/Black |
| 2 | ECT – (Engine Coolant Temp Sensor) | Red/White | Red/White |
| 3 | MAP – (Manifold Absolute Pressure Sensor) | Red/Green | White/Yellow |
| 4 | VCC1 – (Sensor Voltage for MAP) | Yellow/Red | Yellow/White |
| 5 | BKSW – (Brake Switch) | Green/White | Green/White |
| 6 | KS – (Knock Sensor) | Red/Blue | Red/Blue |
| 7 | PHO2S – (Primary Heated O2 Sensor 1) | White | White |
| 8 | IAT – (Intake Air Temp) | Red/Yellow | Red/Yellow |
| 9 | EGRL – (EGR Valve Lift Sensor) Civic ONLY | White/Black | |
| 10 | VCC2 – (Sensor Voltage) | Yellow/Blue | Yellow/Blue |
| 11 | SG2 – (Sensor Ground) | Green/Black | Green/Blue |
| 12 | SG1 – (Sensor Ground) | Green/White | Green/White |
| 13 | SHO2/SG – (Secondary Heated O2 Sensor Ground) (D16Y7) | Red/Yellow | |
| 13 | SHO2/SG – (Secondary Heated O2 Sensor Ground) (D16Y8) | Green/Black | |
| 13 | SHO2/SG – (Secondary Heated O2 Sensor Ground) (Integra) | Orange/Blue | Orange/Blue |
| 14 | SHO2S – (Secondary Heated O2 Sensor 2) | White/Red | Blue/Red |
| 15 | PTANK – (Fuel Tank Pressure Sensor) | Light Green | Light Green |
| 16 | EL (ELD) – (Electric Load Detector) | Green/Red | Green/Red |
OBD2B ECU Pinouts (1999-2000 Honda Civic & Integra)
The OBD2B system was implemented in Honda Civic and Integra models from 1999 to 2000. Below are the pinout diagrams for the connectors on the OBD2B ECU.
Connector “A” Pinouts
OBD2B Connector “A” manages various systems including EVAP, cruise control, and indicator lights, alongside sensor and switch signals.
| Pin | Function | Wire Color (Civic) | Wire Color (Integra) |
|---|---|---|---|
| 1 | Empty Slot | ||
| 2 | Empty Slot | ||
| 3 | 2WBS – (EVAP Bypass Solenoid Valve) | Blue | Blue |
| 4 | VSV – (EVAP Control Canister Vent Shut Valve) | Light Green/White | Light Green/White |
| 5 | CRS – (Cruise Control Signal) | Blue/Green | Blue/Green |
| 6 | PCS – (EVAP Purge Control Solenoid Valve) | Red/Yellow | Red/Yellow |
| 7 | ATPD – (A/T Gear Position Switch) | Yellow | Yellow |
| 8 | SO2SHTC – (Second O2 Sensor Heater Control) | Black/White | Black/White |
| 9 | ATPNP – (A/T Gear Position Switch) | Light Green | Light Green |
| 10 | SCS – (Service Check Signal) | Brown | Brown |
| 11 | Empty Slot | ||
| 12 | Empty Slot | ||
| 13 | Empty Slot | ||
| 14 | D4IND – (A/T D4 Indicator) | Green/Black | Green/Black |
| 15 | Empty Slot (Civic Plug) | ||
| 15 | FLR – (Fuel Pump Relay) (Integra Plug) | Green/Yellow | Green/Yellow |
| 16 | Empty Slot (Integra Plug) | ||
| 16 | FLR – (Fuel Pump Relay) (Civic Plug) | Green/Yellow | Green/Yellow |
| 17 | ACC – (A/C Clutch Relay) | Black/Red | Black/Red |
| 18 | MIL – (Malfunction Indicator Light) | Green/Orange | Green/Orange |
| 19 | NEP – (Engine Speed Pulse) | Blue | Blue |
| 20 | FANC – (Radiator Fan Control) | Green | Green |
| 21 | K-Line – (OBD2 Scan Tool Signal) | Blue/Yellow | Blue/Yellow |
| 22 | ATP L – (A/T Gear Position Switch) | Blue | Blue |
| 23 | SHO2S – (Secondary Heated O2 Sensor 2) | White/Red | White/Red |
| 24 | STS – (Starter Signal Switch) | Green | Green |
| 25 | Empty Slot | ||
| 26 | PSPSW – (Power Steering Power Switch Signal) | Green | Green |
| 27 | ACS – (A/C Switch Signal) | Blue/Red | Blue/Red |
| 28 | SLU – (A/T Brake Related) | White/Red | White/Red |
| 29 | PTANK – (Fuel Tank Pressure) | Light Green | Light Green |
| 30 | EL (ELD) – (Electrical Load Detector) | Green/Red | Green/Red |
Connector “B” Pinouts
Connector “B” on the OBD2B ECU is primarily focused on engine management components such as injectors, idle air control valve, and VTEC solenoid.
| Pin | Function | Wire Color (Civic) | Wire Color (Integra) |
|---|---|---|---|
| 1 | IGP1 – (Power Source) | Yellow/Black | Yellow/Black |
| 2 | PG1 – (Power Ground) | Black | Black |
| 3 | INJ2 – (Injector 2) | Red | Red |
| 4 | INJ3 – (Injector 3) | Blue | Blue |
| 5 | INJ4 – (Injector 4) | Yellow | Yellow |
| 6 | IACVP – (IACV Position Side) Civic ONLY | Black/Blue | |
| 7 | ES (ESOL) – (EGR Control Solenoid Valve) | Red | Red |
| 8 | LS – (HLC LSM) (CVT Transmission Related) | Pink/Black | Pink/Black |
| 9 | IGP2 – (Power Source) | Yellow/Black | Yellow/Black |
| 10 | PG2 – (Power Ground) | Black | Black |
| 11 | INJ1 – (Injector 1) | Black | Black |
| 12 | VTS – (VTEC Solenoid) | Green/Yellow | Green/Yellow |
| 13 | ICM – (Ignition Control Module) | Yellow/Green | Yellow/Green |
| 14 | Empty Slot | Green/Red | Green/Red |
| 15 | IACVN – (IACV Negative Side) Civic ONLY | Orange | |
| 16 | IAB – (Intake Air Bypass Control Solenoid Valve) GSR ONLY | ? | ? |
| 17 | LS+HLC LSM – (A/T CVT Transmission Related) (D16Y7) | Red | |
| 17 | LS+HLC LSM – (A/T CVT Transmission Related) (D16Y5) | Green/White | |
| 18 | SC LSM – (CVT Transmission Related) | Pink/Blue | Pink/Blue |
| 19 | Empty Slot | ||
| 20 | LG1 – (Logic Ground) | Brown/Black | Brown/Black |
| 21 | VBU – (Voltage Backup) | White/Blue | White/Blue |
| 22 | LG2 – (Logic Ground) | Brown/Black | Brown/Black |
| 23 | IACV – (Idle Air Control Valve) | Black/Blue | Black/Blue |
| 24 | Empty Slot | ||
| 25 | SC LSP – (CVT Transmission Related) | Yellow | Yellow |
Connector “C” Pinouts
OBD2B Connector “C” handles crucial sensor data including primary O2 sensor, knock sensor, and various temperature and position sensors.
| Pin | Function | Wire Color |
|---|---|---|
| 1 | PO2SHTC – (Primary O2 Sensor Heater Control) | Black/White |
| 2 | ALTC – (Alternator Control) | White/Green |
| 3 | KS – (Knock Sensor) | Red/Blue |
| 4 | Empty Slot | |
| 5 | ALTF – (Alternator FR Signal) | White/Red |
| 6 | EGRL – (EGR Valve Lift Sensor) | White/Black |
| 7 | SG1 – (Sensor Ground, Ground for MAP) | Green/White |
| 8 | CKKP – (CKP Sensor P-side) | Blue |
| 9 | CKPM – (CKP Sensor M-side) | White |
| 10 | VTM – (VTEC Pressure Switch) | Blue/Black |
| 11 | Empty Slot | |
| 12 | Empty Slot | |
| 13 | Empty Slot | |
| 14 | Empty Slot | |
| 15 | Empty Slot | |
| 16 | PHO2S – (Primary Heated O2 Sensor 1) | White |
| 17 | MAP – (Manifold Absolute Pressure Sensor) | Red/Green |
| 18 | SG2 – (Sensor Ground) | Green/Black |
| 19 | VCC1 – (Sensor Voltage for MAP) | Yellow/Red |
| 20 | TDCP – (TDC Sensor P-side) | Green |
| 21 | TDCM – (TDC Sensor M-side) | Red |
| 22 | CKFP – (CKF Sensor P-side) | Blue/Red |
| 23 | VSS – (Vehicle Speed Sensor) | Blue/White |
| 24 | Empty Slot | |
| 25 | IAT – (Intake Air Temp) | Red/Yellow |
| 26 | ECT – (Engine Coolant Temp Sensor) | Red/White |
| 27 | TPS – (Throttle Position Sensor) | Red/Black |
| 28 | VCC2 – (Sensor Voltage) | Yellow/Blue |
| 29 | CYPP – (CYP Sensor P-side) | Yellow |
| 30 | CYPM – (CYP Sensor M-side) | Black |
| 31 | CKFM – (CKF Sensor M-side) | White/Red |
NTHEFASTLANE’s Top Recommended OBD2A/2B Performance Parts
For those looking to enhance the performance of their OBD2A/2B Honda vehicles, here are some top recommended parts:
- OBD 2A Jumper
- OBD 2B Jumper
- Wideband
- E-Boost Controller
- MAP Sensor
- Pressure Sensor
- ECU Socket Kit
- Boost Gauge
- ECU Chip
- Fuel Pump
- Injectors
- Turbocharger
This guide provides a comprehensive overview of Honda Civic Obd2 Ecu Pinouts, essential for anyone working on these vehicle systems. Always refer to your vehicle’s specific service manual for the most accurate information and procedures.
