The definition of the C1956 Code is required thing and if the engine has a problem the car engine may make trouble and then the engine code reader may show the code when the car engine is tested. Do not try to solve the car engine in your place if you do not have all tools and necessary information. You have expertise. The engine code is available in many car engines and meanings changes for the manufacturers. When you are talking about your car, you should think about the car manufacturer. Your car manufacturer put a meaning of the code and you should use that meaning for solving the car engine problem. The engine code C1956 has automobile meaning and it is necessary to know the right meaning. The automobile meaning of the code is C for Chassis Code Problem is controller area network wiring bus and modules. 1 for MFG – Manufacturer Specific. 9 for Fuel And Air Metering (Injector Circuit Malfunctions Only). 5 for TP Sensor Learn Not Complete and 6 for Cruise Control System – Vehicle Accel Too High. However, the engine system was upsetting, misjudged by customers, and a rash of unpredictable letdowns led to the technology being fast retired.