The engine P0084 is a general code representing an issue with the finish valve control journey on the bank 2 side of the engine. This car engine problem can be caused of Open or short in wiring harness, ECM that has failed, Bank 2 exhaust valve control solenoid is faulty and damaged or broken electrical connector or poor electrical connection. There are some symptoms available for the problem of the car engine. Changing the solenoid before any other checking has been achieved. The fixing of the car engine is easy to solve if the proper meaning of the engine is found.