DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P258A
P258A indicates that the powertrain control module (PCM) has detected an open circuit in the control circuit for the vacuum pump, which is used on some engines to provide brake assist vacuum or to operate emission-related vacuum actuators. The PCM commands the pump on and monitors the circuit for expected voltage or current, and it sets this code when the circuit remains open, meaning no continuity or an unexpected high resistance is present.
Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.
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