The engine makes problem due to the B1994 Code area and that is why, the code reader sends the code. The engine structure, in conjunction with the engine control module or powertrain control module (PCM), starts the B1994 code solenoid valve to control oil compression to the engine mechanism that is connected in the valve scheme to switch valve judgment between High and Low. If the engine solenoid valve has an open, a DTC is kept. This car engine problem is easy to solve if you are an expert. Because the body of the car engine has the problem and you dot need to change any part from the car engine.