P0601 Internal control module memory checksum error
System
Powertrain - engine and transmission
What P0601 means
The official name, 'Internal control module memory checksum error', describes a test the module ran on itself: it added up the contents of its own stored memory and compared that total with the checksum figure kept alongside it, and the two did not agree. Nothing here is a sensor reading — the measurement is arithmetic over the module's own memory, which is what the word internal is doing in the name. Its neighbours in the same family name the other memories the same way: keep-alive memory, random access memory and read only memory each carry their own code.
This is a standard code. It means the same thing on every make of vehicle.
What the program shows for P0601
For a code about the module's own memory, what the program can put on screen is what that module answers: the Full scan's All supported sensors section lists every reading on the program's list this computer replies to, and the Sensor sweep's Listed but silent line names the ones the car claimed in its own supported list and then did not answer when asked. Where one of the code lists could not be read, the Trouble codes tabs print ? in place of a count rather than a zero.
The Full scan's Vehicle identity section reads the VIN, Calibration and Verification number (CVN) straight from the control module, along with the Protocol and Adapter in use, and saves them with the scan. The Trouble Codes screen shows the CHECK ENGINE lamp state the computer reports, and the Dashboard has a System voltage gauge. The Adapter traffic screen shows every request and reply on the wire.