CYLINDER HEAD GP 1566983 - Caterpillar

Operating the engine with a Personality Module not designed for that engine will damage the engine. Be sure the Personality Module is correct for your engine.
Certain other codes require customer passwords. The majority of logged codes do not require passwords to be cleared. Since the factory passwords contain alphabetic characters, the Electronic Technician (ET) may perform these functions. In order to obtain the factory passwords, proceed as if you already have the password. At some point, if the factory passwords are actually needed, the Electronic Technician (ET) will request the factory passwords and the Electronic Technician (ET) will display the information that is required to obtain the passwords.Note: The "Customer Parameter Lockout" may restrict changing some Parameters that are customer programmable unless Factory Passwords are obtained. If changing a Parameter that is customer programmable indicates that the Factory Passwords are required, the Parameter has been Locked Out. Refer to Troubleshooting, "System Configuration Parameters" for additional information.