Open your trainer or Cheat Engine table and select the game process ( NFSC.exe ).
For version 1.4, players generally rely on trainers or save editors. Need For Speed Carbon Trainer 1.4 Unlock All Cars
A powerful script-based mod that can unlock all vehicles, including those originally exclusive to multiplayer. Open your trainer or Cheat Engine table and
If you are using a standard Cheat Engine trainer (like the one by rcgldr), the process is straightforward: Need For Speed Carbon Trainer 1.4 Unlock All Cars
This is a popular "trainer" file designed for use with Cheat Engine 6.7+ . It includes a specific "Unlock all career cars and parts" toggle and even allows you to purchase custom cars like the "Cop Z06" in career mode.