Fix the car engine as soon as possible and for solving the car engine, the right meaning of the engine P278D Code helps to solve the car engine problem. Do not drive the car if the car engine is unfixed. However, the automobile dictionary meaning of the code is not very helpful for solving the car engine. The automobile dictionary meaning of the engine code is P for OBD-II Diagnostic Powertrain (P) Trouble Code For Engine. 2 for Fuel And Air Metering (Injector Circuit Malfunctions Only). 7 for Engine Oil Temperature Sensor Malfunction. 8 for Cylinder 10 Contribution/balance Fault and D for Exhaust Gas Recirculation Sensor B Circuit High.