DTC B1658: EEPROM Checksum Error: Description

Module calibrations are stored in EEPROM. When ignition switch is first turned to ON position, module performs internal tests on EEPROM and can determine integrity of its non-volatile memory. Module compares previously used checksum with checksum calculated when ignition switch is first turned to ON position. If checksums do not match, module will indicate a calibration malfunction (checksum error) is current.

DTC will set when stored checksum does not match calculated checksum. DTC will also set when module detects an internal memory malfunction (checksum error) and when these conditions occur when ignition switch is first turned to ON position.