What OBD protocol does Honda use?
Honda’s modern OBD-II systems primarily use CAN (ISO 15765-4). Older Honda models, depending on the year and market, used ISO 9141-2 or ISO 14230 (KWP2000).
This article examines how Honda’s OBD protocols have evolved, what drivers and technicians should expect on current and legacy models, and how to identify the protocol on a given vehicle. It also explains how to determine the correct diagnostics approach for your specific Honda.
Current OBD-II Protocols in Honda Vehicles
The following overview focuses on the protocol most commonly used by contemporary Honda models for on-board diagnostics and emissions data access.
- CAN (ISO 15765-4) high-speed protocol over the OBD-II connector
CAN is the standardized, high-bandwidth protocol that Honda uses on modern vehicles, enabling broad compatibility with contemporary diagnostic tools. While CAN is the default for most new Hondas, some very early or region-specific models may still rely on legacy protocols.
Historical OBD-II Protocols Used by Honda
Before CAN became the universal standard for OBD-II, Honda deployed older protocols depending on the model year and market. These are largely phased out in new vehicles but may appear on legacy cars or in certain regions.
- ISO 9141-2 (K-Line) – used on older Honda OBD-II implementations
- ISO 14230 (KWP2000) – used on some late-1990s to early-2000s Hondas
These legacy protocols were gradually supplanted by CAN as regulatory requirements and global standards shifted toward a unified OBD-II interface. If you’re working with a mid- to late-1990s Honda, you may encounter these protocols during diagnostics.
How to identify your Honda's OBD protocol
To determine the diagnostic protocol for a specific Honda, you generally need model-year, market, and sometimes VIN information. Many modern scanners auto-detect the protocol, while older tools may require manual selection.
- Check the model year and market (US, EU, JP) to infer likely protocols
- Use a CAN-capable OBD-II scanner and verify communication; if it fails, try ISO 9141-2 or ISO 14230 compatibility
- Consult the vehicle’s service manual or VIN-specific documentation for exact protocol support
In practice, most modern Honda owners will access diagnostics via CAN, while owners of older Hondas may need to configure a scanner to ISO 9141-2 or ISO 14230.
Summary
Today, Honda primarily uses CAN (ISO 15765-4) for OBD-II diagnostics and emissions data in its newer models. Historically, some Honda vehicles used ISO 9141-2 or ISO 14230 (KWP2000) before CAN became universal. Identifying the exact protocol for a given car involves checking the model year, regional market, and, if possible, the vehicle’s service documentation or a capable diagnostic tool. For most current Honda owners and technicians, CAN is the standard pathway for OBD-II access.
