The automobile meaning of the engine C1842 Code is C for Chassis Code Problem is controller area network wiring bus and modules. 1 for MFG – Manufacturer Specific. 8 for Ignition System Or Misfire. 4 for BBV Sensor Circuit Low Voltage and 2 for A/C System High Pressure High Temperature. Do not use this meaning of the code for solving the car engine problem. This meaning of the code is not good information for solving the car engine problem. You may face terrible problem if you follow this meaning of the code. You may bring more problem in the car engine.