Diagnostic article Generic OBD-II
P27D5: Valve-five open-load remains an electrical off-state test
P27D5 checks the synchronizer valve-five circuit when its low-side output is off, independently of rod-five hydraulic motion.
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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.
P27D5 maps to synchronizer actuation valve five’s electrical open-load check. With the low-side output off, the load should pull the monitored node toward the supply. The driver uses a small diagnostic current to test whether the node can instead remain in its defined low window, indicating an absent load path.
Read across the page boundary
Page 928 begins the row; page 929 continues its voltage window, off-time and confirmation requirements. The output must have been off for more than 5 ms, and the fault must meet at least 150 ms confirmation. Ignoring the continuation would omit key conditions.
The controller must be outside safe state with eligible supply voltage. P0882 and P0883 disable this test. Hydraulic motion is not its measured criterion.
Avoid the wrong inference
A rod-five movement failure can motivate further diagnosis but does not independently prove an open valve-five circuit. Conversely, a successful energized command does not repeat the off-state test. Retain driver open-load status and command timing, then use the applicable wiring information to isolate the path. The generic solenoid-S label does not supply a universal connector or identify the failed component by itself.
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
Pressure Control Solenoid S” Control Circuit/Open
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