Diagnostic article Generic OBD-II
P2258: secondary-air relay high circuit is separate from pump-flow performance
GM P2258 records a short-to-battery classification in the AIR relay circuit and depends on the stated supply and powertrain-relay conditions.
Read before applying this article
Documented application
GM 2009 09OBDG06 Engine Diagnostics, cited secondary-air relay high circuit monitor only. Document-level evidence does not establish per-code vehicle, engine or wiring applicability.
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.
P2258 is the high-circuit diagnostic for the secondary-air injection relay in this GM table. The source identifies the electrical condition as a short to battery voltage. That is distinct from the system's separate pressure and air-flow performance tests.
Preserve the electrical classification
The listed evaluation uses the stated ignition conditions, battery voltage above 11 V and absence of the specified powertrain-relay faults. The table gives a one-second condition and a two-driving-cycle classification. A power-supply problem recorded elsewhere may therefore affect how this relay report should be interpreted.
The paired P2257 row includes grounded or disconnected-circuit conditions. Those are different from P2258's high-side classification, even though both codes refer to the AIR relay circuit. The exact code should remain attached to the diagnostic evidence.
Do not jump from relay feedback to a pump replacement
A technician needs the relevant circuit behavior and supply context, followed by the vehicle-specific wiring checks. The monitor table does not determine whether the cause is in wiring, a connector, relay circuitry or control electronics.
It also does not prove that air flow is inadequate or that a switching valve is stuck. Those questions require the applicable functional diagnostics. The source contains no relay-bypass procedure or universal terminal measurements. Professional verification should establish correct circuit operation under its enabling conditions and then address any remaining functional AIR-system faults, rather than assuming that a reset or an audible pump resolves the electrical finding.
Source and applicability
GM 2009 09OBDG06 Engine Diagnostics, cited secondary-air relay high circuit monitor only. Document-level evidence does not establish per-code vehicle, engine or wiring applicability.
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
AIR System Control A Circuit 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