DTC B1009: BCM Internal Memory Malfunction (Checksum Error): Description

WARNING: This page is about a different car, the 1999 Buick Regal and 1999 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

Body Control Module (BCM) calibrations are stored in Electronically Erasable Programmable Read Only Memory (EEPROM). When ignition is first turned to RUN position, BCM performs internal tests on EEPROM and determines integrity of its non-volatile memory. BCM will also compare the present checksum with the checksum previously stored.

DTC B1009 will set when stored checksum does not match calculated checksum, or when an internal memory malfunction (checksum error) is detected by BCM when ignition switch if first turned to RUN position. No driver warning message will be displayed.

If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC B1009 will also clear when conditions no longer exist or when scan tool is used to clear codes.