- Machine Engines:
- 3126 (S/N: 55K1-UP; 6JK1-UP; 4CW1-UP; MHX1-UP; RHX1-UP; RSX1-UP; 98Z1-UP; 3AK1-UP)
Effective 23January 2005 the factory password system was changed to a default of "All password requests for incompatible software and interlock codes will not be allowed". This fundamental system change required Caterpillar to create specific guidelines for acceptable engine software, and interlock code changes. The specific guidelines define compatible software interlock code changes for a given engine serial number prefix or range. What can be allowed has been decided based on iron, software compatibility, and regulatory requirements.
Refer to the Special Instruction REHS1385-09 for 3408 and 3412 Tier I and Tier II emission level machine engine applications. This Special Instruction includes charts for software interlock codes associated with changing from "Prime" to "Non-prime".
Note: The new guidelines do not allow reversing from "Non-prime" to "Prime" since "Non-prime" software contains the latest improvements to the current production.
Note: If interlock codes are found to be incorrect, notify the dealer Technical Communicator (TC) to enter a service request through the Dealer Service Network (DSN). Please provide all Electronic Control Module (ECM) information necessary to generate passwords.
The new guidelines are for diagnostic use only, not for blank or test ECM's.
Do not borrow or use an ECM from any other machine application for diagnostic use.