It is necessary to get the right meaning of the engine code and if the engine P0086 Code is necessary to know read the car engine manual. However, there are several reasons to appear the engine code and those are Wiring harness that has an open or short, Poor electrical connection, ECU that has failed and Failed bank 2 exhaust valve control solenoid. Diagnosis of the car engine is necessary thing for fixing the car engine. Do not drive the with any problem of the car engine. When the car engine is ok, then take the car for a test drive.