The test drive is important for solving the car engine problem of the engine C1456 Code. The real meaning of the code is found from the car manufacturer. Read the manual of the car engine for solving the car engine problem. You can use the general meaning of the code and that is C for Chassis Code Problem is controller area network wiring bus and modules. 1 for MFG – Manufacturer Specific. 4 for Transmission. 5 for TP Sensor Learn Not Complete and 6 for Cruise Control System – Vehicle Accel Too High. Chassis of the car engine is easy to fix at the low cost.