Circuit Description

BCM calibrations are stored in Electronically Erasable Programmable Read Only Memory (EEPROM). When ignition switch is first turned to RUN position, BCM performs internal tests on EEPROM and determines integrity of its non-volatile memory. BCM will also attempt to write to its own non-volatile memory when ignition switch is turned to RUN, then LOCK or OFF position.

DTC B0603 will set when BCM has 3 consecutive unsuccessful attempts at writing to its own non-volatile memory, or when an internal memory malfunction (write error) is detected by BCM. No driver warning message will be displayed.

Under all fault conditions, DTC B0603 requires an ignition cycle from LOCK/OFF to RUN position before the DTC will clear. If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC B0603 will also clear when conditions no longer exist or when scan tool is used to clear codes.