Cars · Sensors
OBD1 16-bit RPM Calculation Reference
Technical reference for calculating 16-bit RPM values in OBD1 Honda ECUs, including the conversion formula and byte order specifications.
To calculate the engine speed from a raw 16-bit RPM value retrieved from an OBD1 ECU, use the following conversion formula:
RPM(x) = 1,875,000 / x
Where x represents the raw 16-bit value.
Important
All 16-bit values in OBD1 ECUs are stored in Little Endian byte order. When reading raw data, ensure the least significant byte (LSB) and most significant byte (MSB) are processed in the correct sequence.