The car engine meaning of the B2509 Code is found online but that is general meaning what must not be helpful. The automobile dictionary meaning of the code is found online and it is B for Body Code Problem is antilock brake system, electronic suspension and steering systems. 2 for MFG – Manufacturer Specific. 5 for Computer And Auxiliary Outputs. 0 for IC Circuit High Voltage and 9 for Kick-Down Switch Failed Short. The poor performing indications are reliable with a MAP sensor fault. The engine system triggers the B2509 code solenoid valve to maintain oil compression to the engine mechanism that is trim in the valve system to change valve timing between High and Low.