Diagnostic article Generic OBD-II
P2257: secondary-air relay low circuit can include an open connection
The GM P2257 example groups short-to-ground and disconnected relay-circuit conditions, so the low label does not isolate one physical fault.
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Documented application
GM 2009 09OBDG06 Engine Diagnostics, cited secondary-air relay low 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.
P2257 concerns the secondary-air injection relay circuit in this GM 2009 example. The source's low-circuit classification includes a short to ground or a connection that is not present. The title alone therefore does not distinguish those two electrical possibilities.
Supply prerequisites belong in the record
The monitor requires the stated ignition and battery-voltage conditions and excludes the listed powertrain-relay faults. A one-second electrical condition is listed, with a two-driving-cycle classification. These qualifications matter before interpreting relay feedback as an isolated AIR-system defect.
The neighboring P2258 record instead concerns a short-to-battery classification. Those directions should not be combined into a single assumption that the relay itself must be bad. The appropriate circuit procedure must establish where the detected condition originates.
Relay electrical integrity is not air-flow verification
A technician should preserve the relay code, supply context and companion powertrain-relay records. The source assigns separate diagnostics to actual secondary-air flow and pressure behavior. An electrical relay fault does not, by itself, establish a blocked passage or a mechanically stuck switching valve.
The table provides no universal connector pinout or instruction to bridge the relay. Use the correct vehicle wiring information and professional diagnostic procedure to separate an open connection from a grounded path or internal component issue. Verification should show correct electrical behavior under the qualified conditions, rather than relying solely on an audible pump or a cleared code.
Source and applicability
GM 2009 09OBDG06 Engine Diagnostics, cited secondary-air relay low 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 Low
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