Diagnostic article Generic OBD-II
P27C7: Valve-three low-circuit diagnosis requires its electrical test context
P27C7 reports a ground-side electrical classification on synchronizer valve three, with command and supply prerequisites.
Read before applying this article
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.
P27C7 concerns the electrical driver path for synchronizer actuation valve three in this GM source. The driver classifies the monitored output as shorted toward ground. This says something about the electrical state and should not be treated as proof that the hydraulic valve cannot move.
Read the continuation before interpreting the test
The narrative starts on page 927, while page 928 supplies switching conditions, supply eligibility and the confirmation interval. The DTC requires at least 150 ms of failure evidence. Reading only the first page would miss qualifications needed to interpret a captured signal.
The controller must be outside safe state, with battery voltage above 8.75 V and below 18 V. P0882 or P0883 inhibits the check. A low node reading during an ineligible supply event is not automatically the documented result.
What verification should answer
Establish whether the driver again reports this fault during the required output state, using the vehicle’s prescribed service method. Keep command timing and fault status together rather than judging an isolated voltage. The generic solenoid-P designation needs mapping to this controller’s valve three. The summary does not independently locate a short or identify a replacement coil, wiring section or control module.
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 P Control 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