The automobile dictionary meaning of the car engine is available and the engine P1542 Code’s meaning is also available. 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. 5 for Computer And Auxiliary Outputs. 4 for BBV Sensor Circuit Low Voltage and 2 for A/C System High Pressure High Temperature. The valves of each cylinder are kept closed using a pair of arms that replace the conventional engine’s roller-type rocker arm. The engine P1542 code is one of these arms what follows the cam profile while the 2nd arm attaches to the valves. During normal engine process the two arms are combined by a locking pin.