Diagnostic article Generic OBD-II
P2854: Clutch-two low pressure must be compared with what the model expects
P2854 uses a sustained low-pressure branch and a broader negative model-error branch under defined clutch-two control conditions.
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Documented application
2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred.
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.
P2854 corresponds to clutch-two pressure control too low in this source. The clearest branch combines a modeled pressure above 1 bar with measured pressure below 0.5 bar for at least five seconds. A low reading without the model’s expectation is not the full diagnostic condition.
Control transitions are excluded
The redundant shutdown valve must be hydraulically on. The controller excludes relevant electrical faults, recovery requests and adaptive overrides of valve current, fast filling or flow influence. Superfill must be inactive, with more than 80 ms since it ended. These gates prevent deliberate special control phases from being interpreted as ordinary pressure-tracking failures.
Another branch rejects an excessive absolute pressure-model difference when the measured value is lower. Its precise difference and time calibrations are referenced by the source rather than guessed here.
Retain model and sensor together
Verification should preserve pressure, modeled pressure, elapsed fault time and the qualifying clutch-two state. A later normal pressure alone cannot identify which branch originally failed. The generic discharge-performance name is narrower here than a complete hydraulic diagnosis: it reports low control performance but does not prove a particular leakage path, valve defect or clutch repair.
Document scope and source
2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred. These figures explain the cited controller logic, not a vehicle-specific repair instruction. Match the vehicle’s service information before applying them.
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
Clutch B Pressure Discharge Performance
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