You need to fix the car engine and the car engine P1813 Code is important thing what is fully meaningful. The engine code comes with the proper information of the car engine problem and location of the problem. If you know the general meaning of the code, you may learn soothing about the problem. The automobile dictionary 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. 1 for Low Coolant Circuit and 3 for Transmission Control Module Reprogrammable Memory. It is better if you look for the real/correct meaning of the code.