Due to several reasons the engine C1865 Code has become visible. The main problem is related with the car engine chassis and it is important to check the rest of the issues. Those are Fuel Temperature Sensor B Circuit Range or Performance, Cylinder 4 Contribution or Balance Fault and Ignition Coil A Primary or Secondary Circuit Malfunction. The oxygen sensors on your car portion the oxygen in the finish to determine how rich or lean the ratio of fuel and air are in the cylinders. Enhancing this mixture means better fuel use and fewer finish emissions. Once the car engine is ok, take the car for a test drive.