DTC B1009: EEPROM Checksum Error: Description

Module calibrations are stored in the EEPROM. When ignition switch is first turned to ON position, module performs internal tests on the EEPROM and can determine integrity of its non-volatile memory.

Module compares its previously stored checksum with checksum calculated when ignition switch is first turned to ON position. If 2 checksums do not match calculated checksum, module will indicate a calibration malfunction (checksum error) and DTC will set. When DTC is set, microprocessor will operate from preset critical operating data for those blocks of data that have failed check sum test. Blocks of data that have not failed check sum test are not affected.

DTC will clear when microprocessor runs a successful check sum test of EEPROM.