Diagnostic article Generic OBD-II
P258D: High vacuum-pump control circuit does not prove excess vacuum
See how GM distinguishes a voltage-side brake-vacuum pump circuit fault from an open circuit, ground fault or pressure-response failure.
Read before applying this article
Documented application
GM 2009 09OBDG02 Engine Diagnostics, LNF-specific section, with the brake-booster pump monitor expressly restricted to GMX020/023 applications. This does not establish broader vehicle fitment or a complete brake service procedure.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P258D is the high-side electrical fault for the vacuum-pump control circuit in this GM monitor. The source names the brake-booster vacuum pump and describes continuity toward voltage. It does not identify excessive vacuum, a pressure limit or proof that the pump is continuously rotating.
Use the driver's classification carefully
GM's threshold is internal to the output-driver circuit. That matters because “high” cannot be converted from this summary into a particular external meter reading, connector location or failed relay contact. The code reports the controller's classification; vehicle-specific wiring and test information are needed to isolate the cause.
P258A marks the open-circuit branch, while P258C marks continuity toward ground. If a diagnostic report includes more than one branch, retain the individual events and their sequence instead of treating the names as interchangeable descriptions of a worn pump.
Pressure response is a separate question
The neighboring P258B monitor evaluates pressure change while the pump is activated. A valid control circuit does not independently prove adequate vacuum production, and a high electrical fault does not measure vacuum performance. A meaningful verification therefore identifies which monitor completed and whether the applicable functional check also passed.
This table lists a 0.01-second primary interval and two-driving-cycle failure recognition. Its application note restricts the brake-booster pump entries to GMX020/023 in the LNF-specific section. Because brake assistance is involved, professional confirmation must follow the vehicle procedure; pump sound, warning-lamp status or a reset alone cannot establish acceptable braking function.
Source and applicability
GM 2009 09OBDG02 Engine Diagnostics, LNF-specific section, with the brake-booster pump monitor expressly restricted to GMX020/023 applications. This does not establish broader vehicle fitment or a complete brake service procedure.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Vacuum Pump Control Circuit A High
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT