The engine P278B Code is very important thing and you need to apply the correct meaning of the code for solving the car engine. Do not drive the car until the car engine is ok and for solving the car engine do not use any meaning of the code. The automobile dictionary meaning of the 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 B for Exhaust Gas Recirculation Sensor B Circuit High.