You need to know the meaning of the B1590 Code for solving the problem of the faulty engine and it is necessary to get the meaning of the code. To get the meaning of the code, you have to know the model and name of the manufacturer. The code B1590 has several meanings based on the manufacture and models, that is why, you have to get the manual. The general meaning of the code is b for Body Code Problem is antilock brake system, electronic suspension and steering systems. 1 for MFG – Manufacturer Specific. 5 for Computer and Auxiliary Outputs. 9 for Crankshaft Position Sensor Circuit Performance and 0 means Transmission Engaged At High Throttle Angle.