The general meaning of the U1806 Code is automobile meaning and automobile meaning of the code is found online but do not use the general meaning of the code for solving the car engine problem. The automobile dictionary meaning of the code is U for Network Code Problem is climate control system, lighting, airbags, etc. 1 for MFG – Manufacturer Specific. 8 for Ignition System Or Misfire. 0 for IC Circuit High Voltage and 6 for Cruise Control System – Vehicle Accel Too High. You can read this meaning of the code for understanding the problem well but you should use real meaning of the code.