Fault Family System: Powertrain (P-Codes) 11 SAE Codes

Vacuum Supply Control

Diagnostic & Technical Explanation

Code P257A (Vacuum Reservoir Control Circuit/Open) sets when the ECM detects an open circuit, out-of-range voltage, or a performance fault while driving the electric vacuum pump (pump A or B) or the vacuum reservoir's control solenoid that together supply vacuum for the brake booster and emissions actuators on engines that generate little manifold vacuum. Causes are a worn vacuum pump motor, a leaking reservoir check valve making the pump run continuously, or damaged control wiring.

These 11 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 11 times.

Codes in this family (11)

Code	Definition	Repair coverage
P257A	Vacuum Reservoir Control Circuit/Open	4 ranked fixes
P257B	Vacuum Reservoir Control Circuit Low	4 ranked fixes
P257C	Vacuum Reservoir Control Circuit High	4 ranked fixes
P258A	Vacuum Pump Control Circuit A/Open	4 ranked fixes
P258B	Vacuum Pump Control Circuit A Range/Performance	4 ranked fixes
P258C	Vacuum Pump Control Circuit A Low	4 ranked fixes
P258D	Vacuum Pump Control Circuit A High	4 ranked fixes
P25EE	Vacuum Pump Control Circuit B/Open	4 ranked fixes
P25EF	Vacuum Pump Control Circuit B Range/Performance	4 ranked fixes
P25F0	Vacuum Pump Control Circuit B Low	4 ranked fixes
P25F1	Vacuum Pump Control Circuit B High	4 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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