VTI Technical Library

Technical Wiring Documents & ECU Pinouts

Honda ECU pinouts, chassis connector diagrams, and manufacturer references for planning, installation, and troubleshooting.

Pinouts & reference library

Choose the reference that matches your hardware. The links below include diagrams, manuals, and manufacturer resource pages.

Identify your ECU and chassis connections

Use these references to plan a harness build, ECU conversion, or standalone installation. Identify the chassis, engine, ECU model, transmission, and connector layout before selecting wiring. An engine swap may combine parts from several generations.

OBD2 connector reference

These common US-market manual-transmission applications are a starting point for identifying ECU connectors, not a guarantee that a harness fits every trim or swapped vehicle.

Reference: HA Motorsports' OBD2A application guide and OBD2B application guide. Automatic-transmission and imported applications require separate verification.

Earlier chassis and conversions: Do not assume that an older chassis already has the OBD1 wiring needed for a P28 or Hondata installation. Confirm the existing ECU plugs, distributor, injector connections, and any conversion harness before using an OBD1 pinout.

Harness and ECU integration

The chassis wiring, engine-side loom, and ECU connection must work together. A matching plug alone does not confirm that the pin assignments or supported circuits match your build.

• Honda OBD1 / Hondata S300: Match the ECU and engine loom to the chassis integration required for your vehicle.
• Link and other standalone ECUs: Use the documentation for the exact ECU model, then confirm trigger, ignition, injector, and sensor requirements.
• Sensor wiring: Check the sensor pinout, supply voltage, grounding requirements, and ECU calibration against the manufacturer's documentation.

Distributor and ignition wiring

Distributor, coil-on-plug, and external trigger configurations use different connections. Match the diagram to the actual hardware and connector view; do not select a pinout from engine family alone.

Grounding and power distribution

Plan the battery ground, engine ground, starter, alternator, and fuse-box connections as part of the system. Use ECU-specific documentation for sensor grounds and power supplies, and confirm the cable routing and circuit protection for your installation.

Find the wiring for your build

Use the product details to confirm fitment, connector options, included components, and lead times.

• VTI engine harnesses — production engine looms and their available configurations.
• Chassis subharnesses — integration between the engine loom and vehicle.
• OBD1 / Hondata S300 wiring and Link ECU wiring — browse by ECU platform.
• K-swap conversion harnesses and adapters — application-specific K-series integration.
• VTI power and ground cable kit — 4AWG OFC cable, DR-25 sleeving, and front/rear alternator options for the listed applications.

Need help matching the system? Submit a custom harness inquiry with the vehicle, engine, ECU, transmission, and wiring scope.