The Data Link Connector (DLC) is the diagnostic interface port used to communicate with Honda Engine Control Units (ECUs). Depending on the vehicle's model year and On-Board Diagnostics (OBD) generation, Honda utilizes either a proprietary legacy 3-pin connector or the standardized SAE 16-pin J1962 connector.

3-Pin Data Link Connector (OBD0/OBD1)#

On OBD0 and OBD1 vehicles (roughly 1988–1995), Honda utilized a proprietary 3-pin DLC port to transmit serial K-Line diagnostic data.

Configuration#

• 3-Wire Models: Include a constant +12V power supply, ground, and a serial data line. This allows diagnostic scanners to power directly from the port.
• 2-Wire Models: Contain only the ground and serial data lines. Diagnostic tools used on these models must be powered by an external source.
• Service Check Connector (SCS): The 3-pin DLC is located adjacent to a separate 2-pin blue connector. Shorting the SCS connector (with a jumper or paperclip) is the standard method for reading flashing diagnostic codes on the dashboard CEL.

Common Locations#

• 1992–1995 Civic / 1993–1995 del Sol: Right lower edge of the passenger dash.
• 1994–1995 Accord (L4): Right lower edge of the passenger dash.
• 1992–1995 Prelude: Behind the front of the center console.
• 1995 Odyssey: Behind the passenger glove box.

16-Pin Data Link Connector (OBD2)#

Honda adopted the standardized 16-pin OBD2 DLC (SAE J1962) beginning with the V6 Accord in 1995, and it became standard on all USDM vehicles by 1996.

Technical Details#

• Communication Protocol: Honda utilizes the ISO 9141-2 protocol for OBD2 communications, primarily using Pins 7 (K-Line) and 15 (L-Line).
• Pin Configuration: While 16 pins are present, Honda typically populates only 7 for standard emissions diagnostics. Other pins are reserved for proprietary systems (ABS, SRS, etc.).

Common Locations#

• Under Driver Dashboard (Facing Down): 1998–2002 Accord, 1996–2000 Civic, 1996–1997 Passport.
• Behind Center Console Ashtray/Trim: 1995–1997 Accord (V6/L4), 1996–1997 Odyssey, 1996–1997 del Sol, 1997–2001 CR-V, 1997–2001 Prelude.