The engine P1751 Code is a vital part of the car engine. When the car engine code come on the car engine code reader, it means that the problem is found in the car engine. You should fix the car engine problem properly and fix the car engine according to the meaning of the car manufacturer. The automobile dictionary meaning of the code is p for Powertrain Code Problem is related engine, transmission and emissions systems. 1 for MFG – Manufacturer Specific. 7 for Auxiliary Emission Controls. 5 for TP Sensor Learn Not Complete and 1 for TFP Valve Position Switch-Drive Without Drive Ratio.