Diagnostic article Generic OBD-II
P26E8: Supply D circuit low includes a high-current failure branch
P26E8 checks HSO8 against battery voltage and a current limit after the transmission shutdown-path test has passed.
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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.
The P26E8 row monitors transmission high-side output eight. It accepts either voltage below 40% of battery voltage or measured current above 5 A as a failure. The second branch is important: a circuit-low label can summarize excess-current evidence even when a later voltage snapshot appears normal.
Establish whether the monitor was enabled
The controller requires a successful shutdown-path test. Battery voltage must lie above 8.75 V and below 18 V, the engine must not be cranking and the key state must not be stop. P0882 and P0883 inhibit the check. The listed confirmation period is at least 60 ms.
A startup or supply disturbance outside that window is not automatically the same event as an eligible HSO8 fault.
Preserve the two branches
Useful diagnostic data includes HSO8 voltage, current feedback and the prior path-test status. Looking only for a continuously low voltage can overlook a transient overload classification. The current figure is a monitor threshold, not a service instruction to force the circuit to that value. Identify the exact output and connected load using the vehicle’s service information. The source does not determine which component created the fault or provide a universal replacement recommendation.
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
Actuator Supply Voltage D 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