Cars · Ecu
EPROM Compatibility for Honda OBD0 and OBD1 ECUs
Understand which EPROM types are pin-compatible with common Honda OBD0 and OBD1 ECUs and their programming requirements.
An EPROM (Erasable Programmable Read-Only Memory) is a programmable ROM that can be written using a ROM programmer or burner.
Pin-Compatible EPROM Types
The 27C256 and 29C256 are the most common EPROM variants that maintain full pin compatibility with Honda OBD0 and OBD1 ECUs.
Warning
The 28C256 is not pin-compatible with Honda OBD0 and OBD1 ECUs and cannot be used as a direct replacement.
27C256
- Type: UV-erasable EPROM
- Capacity: 32 KB
- Compatibility: OBD0, OBD1
- Notes: Requires UV eraser for reprogramming; reusable
29C256
- Type: Electrically erasable EPROM (EEPROM)
- Capacity: 32 KB
- Compatibility: OBD0, OBD1
- Notes: In-circuit reprogrammable; no external eraser required
Incompatible Types
| Type | Reason | Status |
|---|---|---|
| 28C256 | Pin configuration mismatch | Not compatible |
Tip
When selecting an EPROM for your Honda ECU tuning project, verify pin compatibility with your specific OBD revision before purchase.