You must not try to solve the car engine when you detect any problem in the car engine. You take the car to automobile repair center where you will get help from expert. The car engine P1381 Code is found by the test of the car engine and some expensive machines are necessary to test the car engine and know about the car engine problem. 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. 3 for IC Module 4X Ref Circuit Intermittent, No Pulses. 8 for Exhaust Gas Recirculation System Valve 1 and 1 for TFP Valve Position Switch-Drive Without Drive Ratio.