Circuit Description

An Electronically Erasable Programmable Read Only (EEPROM) is used to contain the program information and calibrations required for engine, transmission and powertrain diagnostics operation. Powertrain Control Module (PCM) uses a value called a checksum for error detection of software. Checksum is a value that is equal to all numbers in software added together. PCM adds all values in the software and if that value does not equal the checksum value, a DTC will set.

Condition for setting this DTC is as follows:

• PCM detects more than 3 incorrect checksums.