Code Definition

P258B — Vacuum Pump Control Circuit ‘A’ Range/Performance

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P258B

P258B is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P258B is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P258B is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The Powertrain Control Module monitors the control circuit for the electric vacuum pump that supplies vacuum for the brake booster and other systems that depend on vacuum. Many turbocharged and direct injection engines, and stop start vehicles, use this pump because the engine does not always produce enough manifold vacuum on its own. DTC P258B sets when the PCM detects that control circuit A is operating outside its expected performance range while the pump is commanded on or off, such as an unexpected duty cycle response, incorrect voltage feedback, or insufficient vacuum for the command. Th...

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