The term OBD1 colloquially refers to Honda engine electronics used roughly from 1992 to 1995, though some Accords and Preludes utilized similar connector configurations as early as 1990. Unlike OBD2, OBD1 is not a standardized regulatory protocol, but rather Honda's specific engineering approach to engine management during this period.

Popular OBD1 ECU Models#

OBD1 ECUs (standardized on 3 grey connectors) are highly prized in the tuning community due to their modular motherboard architecture, which allows for easy socketing and custom firmware (ROM) development.

Civic/Integra Applications#

• P05: 92-95 Civic CX (D15B)
• P06: 92-95 Civic DX (D15B)
• P07: 92-95 Civic VX (D15Z1)
• P08: 92-95 Civic/CRX VTi/VXi (SOHC VTEC)
• P28: 92-95 Civic Si/EX (SOHC VTEC D16Z6)
• P30: 92-95 Del Sol DOHC VTEC Si / EG SiR
• P61: 92-93 Integra GSR
• P72: 94-95 Integra GSR
• P74/75: 94-95 Integra RS/LS/GS
• PR3/PR4: Early 90s JDM/USDM Integra performance variants

Accord/Prelude Applications#

• P0A: 94-95 Accord EX (F22B)
• P13: 93-95 Prelude VTEC (H22A)
• P14: 93-95 Prelude Si (H23A non-VTEC)
• PT3: 90-93 Accord (F22A non-VTEC)

Specialized & JDM Applications#

• PR7: 91-94 NSX (C-series V6)
• Various JDM-Specific Models: Include P27 (Euro/Asian), P29 (Domani), P51/P54 (Accord/Domani variants), and P76 (Integra ZC).

Note: ECU identification and compatibility depend heavily on production region, chassis, and engine type. Always verify the ECU part number against factory service documentation when performing swaps or tuning.