This guide provides visual documentation and component identification for modifying common Honda ECUs to support custom ROM tuning.

OBD0 ECU Modifications#

PM6 and Related Series#

Covers 1990–1991 PM6, PM7, PR5, PR4, and PP5 ECUs.

• Chipping an OBD0 PM6 ECU0

1988–1989 Variants#

Covers early OBD0 ECU hardware configurations.

• Chipping a 1988-1989 ECU0

OBD1 ECU Modifications#

Big-Case ECUs#

Covers USDM, EDM, and early JDM big-case ECU variants.

• Chipping an OBD1 big-case ECU0

Small-Case ECUs#

Covers small-case JDM ECU hardware configurations.

• Chipping an OBD1 small-case ECU0

Important

Ensure the ECU board revision matches the specific guide before beginning any soldering or component removal. Verify all jumper settings and socket orientations against the provided visual references.

Caution

Static electricity can damage sensitive ECU components. Always use an anti-static wrist strap and a grounded workstation when performing board-level modifications.