Diagnostic article Generic OBD-II
P2157: A group D high-supply fault is checked with the driver switched off
Learn why GM P2157 compares injector high-side feedback with controller power during an off command.
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Documented application
2025 GM 03B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file.
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.
P2157 identifies a high condition in injector group D's supply circuit. GM's documented implementation watches the channel named injector 4 high-side driver while it is powered off. Feedback that remains close to controller power supports the source's short-to-power classification.
The off state is essential to the interpretation
The table specifies a difference of no more than one volt between the signal and controller power for its electrical criterion. This is a relative measurement, not an instruction that the output must measure one volt relative to chassis ground. Confusing those references would change the test's meaning.
Battery voltage must be at least 11 V, engine runtime at least one second and the relevant P062B fault states absent. The monitor confirms ten failures in twenty samples at a 100-millisecond task rate, with one-trip reporting.
Retain both command and voltage reference
A high feedback level during a legitimate on command does not reproduce the documented off-state failure. Preserve the command and the relationship to controller power at the event rather than judging an isolated signal voltage.
The group-D identity and GM's injector-4 naming do not provide a universal physical cylinder or connector location. Nor does the monitor distinguish a connection toward power inside the load, harness or controller. Use the applicable circuit information to resolve that path before selecting a component or treating this electrical result as excessive fuel delivery.
Source and applicability
2025 GM 03B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 790.
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
Fuel Injector Group D Supply Voltage 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