%META:TOPICINFO{author="blundar" date="1078511460" format="1.0" version="1.1"}% A Checksum is a very basic form of error checking. A checksum is calculated by adding the values of a ROM together, without any form of carry or overflow checking. Checksums can vary in size - 8bit, 16bit, 32bit checksums are all common. OBD0 and OBD1 honda ECUs use exclusively 8 bit checksums i.e. checksums from 0 -> 255 decimal, 00-FF hex.

There is a program called check8 (also available attached to this page) that can calculate 8bit checksums. %META:FILEATTACHMENT{name="Check8.exe" attr="" comment="Keil's 8 bit checksum utility" date="1078511385" path="C:\Documents and Settings\Administrator\Desktop\temp\wiki\Check8.exe" size="10308" user="blundar" version="1.1"}%