Diagnostic article Generic OBD-II
P0867: transmission pressure fails to build with pump power available
P0867 identifies failure to build minimum transmission system pressure in the cited monitor.
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Documented application
2025 GM 25OBDG07A Part2 diagnostic monitor documentation; the application-matrix filename mismatch is unresolved, so no model or engine 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.
P0867 identifies failure to build minimum transmission system pressure in the cited monitor. It is a performance check made when the controller expects hydraulic power to be available.
The pressure floor is conditional
The documented failure threshold is measured system pressure below 4 bar for 2,000 milliseconds. The system-pressure sensor must have no electrical fault. Hydraulic power must be available from the main pump, or a target speed must be requested from the auxiliary pump.
The application must not be in bypass state, and the diagnostic is disabled during the specified auxiliary-pump priming mode. A low pressure reading while the pump is not expected to supply pressure is therefore different from the enabled failure.
Useful interpretation
This code checks failure to establish a minimum pressure, not simply a difference from a changing target. Compare the pump-power/request state with pressure and the sensor’s electrical validity. The code alone does not prove that a particular pump is physically defective.
Verification should show pressure building appropriately when the same hydraulic availability conditions exist and the no-pressure monitor completes. A pressure value taken after the event without pump-state context is incomplete evidence. Transmission hydraulic testing should follow the correct professional procedure; the published four-bar threshold is not a universal service-pressure specification.
Documentation and applicability
These details describe the monitor in GM’s 2025 25OBDG07A Part2 file. Its application-matrix filename does not match the download index, so model and engine applicability remain unresolved. Use the vehicle’s correct service information before applying these calibration details.
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
Transmission Fluid Pressure
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