The DTC P0602 OBD2 means that the PCM (Powertrain Control Module) has found an internal programming error. This error applies to itself.
The information contained in the PCM is essential for proper engine management. It is programmed at the factory in EEPROM (electrically erasable programmable ROM) memory. Specific settings that are used for engine and transmission management are programmed into the EEPROM. This memory not only aids in the efficient engine management and performance but also helps to recognize and interact with other control modules in the vehicle.
If the PCM finds faults in the EEPROM or does not recognize the EEPROM program, it stores this code along with the Check Engine light.