The diagnosis B1387 Code is a definition of the fault of the engine. Perhaps the problem generates from the body of the engine. According to the model and manufacturer, the definition of the code is changed. All the parts of this code has a meaning and it is necessary to know all the meanings. All those meanings are B for Body Code Problem is antilock brake system, electronic suspension and steering systems. 1 for MFG – Manufacturer Specific. 3 for IC Module 4X Ref Circuit Intermittent, No Pulses. 8 for Exhaust Gas Recirculation System Valve 1. 7 for Cruise Inhibit Control Circuit.