CAT 3406E (Prefix 1MM or 2WS) Fault Code: 59 PID: SPN: 252 FMI: 11 Engine Software Incorrect2025-04-05T20:28:29Z The Engine Control Module (ECM) detects incorrect engine software . Probable Causes: 1) New ECM on vehicle, needs to be programmed2) Current ECM programmed incorrectly3) ECM Connection/harness Back to blog