The meaningful B1865 Code may come from your car when the car engine is diagnosed. You need to study the dictionary meaning of the code for solving the problem. The dictionary meaning of the code is B for Body Code Problem is antilock brake system, electronic suspension and steering systems. 1 for MFG – Manufacturer Specific. 8 for Ignition System or Misfire. 6 for Control Module Throttle Actuator Position Performance and 5 for Park or Neutral Position (PNP) Switch Circuit Engine Torque Signal Circuit. By the dictionary meaning of the code, it is easily noted that the body of the engine has the main problem.