Circuit Description

The control module contains a section of non-volatile memory where it stores data values it needs to save when ignition is turned off. This is referred to as the keep alive memory. After ignition is turned off, control module adds the data in all of these memory locations. This value is called the checksum. The control module also performs the same function when the ignition is turned on. If at key on the checksums do not match, this DTC will be set. DTC will set if a difference was detected in data stored in the keep-alive memory at power-down when compared with data retrieved from the keep-alive memory at power-up.