The engine P1738 Code lets you know to solve the car engine and it is important to identify the problem of the car engine. The powertrain of the car engine is faulty here and you need to fix the car engine by the correct meaning of the code. The automobile dictionary meaning of the code is found online and it is p for Powertrain Code Problem is related engine, transmission and emissions systems. 1 for MFG – Manufacturer Specific. 7 for Auxiliary Emission Controls. 3 for Cruise Control Servo Indicates Low and 8 for PCM Stack Overrun. Finally, a test drive necessary.