This engine P1854 Code gives more information and the general meaning of the code is p for Powertrain Code Problem is related engine, transmission and emissions systems. 1 for MFG – Manufacturer Specific. 8 for Ignition System Or Misfire. 5 for TP Sensor Learn Not Complete and 4 for Cruise Vehicle Speed/Set Speed Difference Too High. The engine code tells about the powertrain problem and this problem can fixed easily. If there is a part that desires fixing, leave it to the specialists. Except of course, you are self-assured that you can demeanor all these maintenances at home. You will need comparatively expensive replacement component and tools for this though.