DTC B1004: Keep Alive Memory (KAM): Description

DTC B1000 is an internal fault and is handled inside control module. No external circuits are used. Module microprocessor must be active/awake for DTC to set. Microprocessor calculates a check sum on those areas of memory that hold critical operation data at regular intervals (periodic check sum). Microprocessor also calculates a check sum when new data is written (running check sum).

Microprocessor compares periodic check sum to running check sum. If they do not match, DTC B1004 will set. When DTC is set, microprocessor will operate from preset critical operating data until new data is learned and stored in KAM.

DTC will clear when microprocessor calculates a successful comparison of periodic check sum to running check sum.